//go:build (sam && atsamd51) || (sam && atsame5x) // Peripheral abstraction layer for the atsamd51. // // Datasheet: // http://ww1.microchip.com/downloads/en/DeviceDoc/60001507C.pdf package machine import ( "bytes" "device/arm" "device/sam" "encoding/binary" "errors" "runtime/interrupt" "unsafe" ) const deviceName = sam.Device func CPUFrequency() uint32 { return 120000000 } const ( PinAnalog PinMode = 1 PinSERCOM PinMode = 2 PinSERCOMAlt PinMode = 3 PinTimer PinMode = 4 PinTimerAlt PinMode = 5 PinTCCPDEC PinMode = 6 PinCom PinMode = 7 PinSDHC PinMode = 8 PinI2S PinMode = 9 PinPCC PinMode = 10 PinGMAC PinMode = 11 PinACCLK PinMode = 12 PinCCL PinMode = 13 PinDigital PinMode = 14 PinInput PinMode = 15 PinInputPullup PinMode = 16 PinOutput PinMode = 17 PinTCCE PinMode = PinTimer PinTCCF PinMode = PinTimerAlt PinTCCG PinMode = PinTCCPDEC PinInputPulldown PinMode = 18 PinCAN PinMode = 19 PinCAN0 PinMode = PinSDHC PinCAN1 PinMode = PinCom ) type PinChange uint8 // Pin change interrupt constants for SetInterrupt. const ( PinRising PinChange = sam.EIC_CONFIG_SENSE0_RISE PinFalling PinChange = sam.EIC_CONFIG_SENSE0_FALL PinToggle PinChange = sam.EIC_CONFIG_SENSE0_BOTH ) // Callbacks to be called for pins configured with SetInterrupt. Unfortunately, // we also need to keep track of which interrupt channel is used by which pin, // as the only alternative would be iterating through all pins. // // We're using the magic constant 16 here because the SAM D21 has 16 interrupt // channels configurable for pins. var ( interruptPins [16]Pin // warning: the value is invalid when pinCallbacks[i] is not set! pinCallbacks [16]func(Pin) ) // Hardware pins const ( PA00 Pin = 0 PA01 Pin = 1 PA02 Pin = 2 PA03 Pin = 3 PA04 Pin = 4 PA05 Pin = 5 PA06 Pin = 6 PA07 Pin = 7 PA08 Pin = 8 // peripherals: TCC0 channel 0, TCC1 channel 4 PA09 Pin = 9 // peripherals: TCC0 channel 1, TCC1 channel 5 PA10 Pin = 10 // peripherals: TCC0 channel 2, TCC1 channel 6 PA11 Pin = 11 // peripherals: TCC0 channel 3, TCC1 channel 7 PA12 Pin = 12 // peripherals: TCC0 channel 6, TCC1 channel 2 PA13 Pin = 13 // peripherals: TCC0 channel 7, TCC1 channel 3 PA14 Pin = 14 // peripherals: TCC2 channel 0, TCC1 channel 2 PA15 Pin = 15 // peripherals: TCC2 channel 1, TCC1 channel 3 PA16 Pin = 16 // peripherals: TCC1 channel 0, TCC0 channel 4 PA17 Pin = 17 // peripherals: TCC1 channel 1, TCC0 channel 5 PA18 Pin = 18 // peripherals: TCC1 channel 2, TCC0 channel 6 PA19 Pin = 19 // peripherals: TCC1 channel 3, TCC0 channel 7 PA20 Pin = 20 // peripherals: TCC1 channel 4, TCC0 channel 0 PA21 Pin = 21 // peripherals: TCC1 channel 5, TCC0 channel 1 PA22 Pin = 22 // peripherals: TCC1 channel 6, TCC0 channel 2 PA23 Pin = 23 // peripherals: TCC1 channel 7, TCC0 channel 3 PA24 Pin = 24 // peripherals: TCC2 channel 2 PA25 Pin = 25 // peripherals: TCC2 channel 3 PA26 Pin = 26 PA27 Pin = 27 PA28 Pin = 28 PA29 Pin = 29 PA30 Pin = 30 // peripherals: TCC2 channel 0 PA31 Pin = 31 // peripherals: TCC2 channel 1 PB00 Pin = 32 PB01 Pin = 33 PB02 Pin = 34 // peripherals: TCC2 channel 2 PB03 Pin = 35 // peripherals: TCC2 channel 3 PB04 Pin = 36 PB05 Pin = 37 PB06 Pin = 38 PB07 Pin = 39 PB08 Pin = 40 PB09 Pin = 41 PB10 Pin = 42 // peripherals: TCC0 channel 4, TCC1 channel 0 PB11 Pin = 43 // peripherals: TCC0 channel 5, TCC1 channel 1 PB12 Pin = 44 // peripherals: TCC3 channel 0, TCC0 channel 0 PB13 Pin = 45 // peripherals: TCC3 channel 1, TCC0 channel 1 PB14 Pin = 46 // peripherals: TCC4 channel 0, TCC0 channel 2 PB15 Pin = 47 // peripherals: TCC4 channel 1, TCC0 channel 3 PB16 Pin = 48 // peripherals: TCC3 channel 0, TCC0 channel 4 PB17 Pin = 49 // peripherals: TCC3 channel 1, TCC0 channel 5 PB18 Pin = 50 // peripherals: TCC1 channel 0 PB19 Pin = 51 // peripherals: TCC1 channel 1 PB20 Pin = 52 // peripherals: TCC1 channel 2 PB21 Pin = 53 // peripherals: TCC1 channel 3 PB22 Pin = 54 PB23 Pin = 55 PB24 Pin = 56 PB25 Pin = 57 PB26 Pin = 58 // peripherals: TCC1 channel 2 PB27 Pin = 59 // peripherals: TCC1 channel 3 PB28 Pin = 60 // peripherals: TCC1 channel 4 PB29 Pin = 61 // peripherals: TCC1 channel 5 PB30 Pin = 62 // peripherals: TCC4 channel 0, TCC0 channel 6 PB31 Pin = 63 // peripherals: TCC4 channel 1, TCC0 channel 7 PC00 Pin = 64 PC01 Pin = 65 PC02 Pin = 66 PC03 Pin = 67 PC04 Pin = 68 // peripherals: TCC0 channel 0 PC05 Pin = 69 // peripherals: TCC0 channel 1 PC06 Pin = 70 PC07 Pin = 71 PC08 Pin = 72 PC09 Pin = 73 PC10 Pin = 74 // peripherals: TCC0 channel 0, TCC1 channel 4 PC11 Pin = 75 // peripherals: TCC0 channel 1, TCC1 channel 5 PC12 Pin = 76 // peripherals: TCC0 channel 2, TCC1 channel 6 PC13 Pin = 77 // peripherals: TCC0 channel 3, TCC1 channel 7 PC14 Pin = 78 // peripherals: TCC0 channel 4, TCC1 channel 0 PC15 Pin = 79 // peripherals: TCC0 channel 5, TCC1 channel 1 PC16 Pin = 80 // peripherals: TCC0 channel 0 PC17 Pin = 81 // peripherals: TCC0 channel 1 PC18 Pin = 82 // peripherals: TCC0 channel 2 PC19 Pin = 83 // peripherals: TCC0 channel 3 PC20 Pin = 84 // peripherals: TCC0 channel 4 PC21 Pin = 85 // peripherals: TCC0 channel 5 PC22 Pin = 86 // peripherals: TCC0 channel 6 PC23 Pin = 87 // peripherals: TCC0 channel 7 PC24 Pin = 88 PC25 Pin = 89 PC26 Pin = 90 PC27 Pin = 91 PC28 Pin = 92 PC29 Pin = 93 PC30 Pin = 94 PC31 Pin = 95 PD00 Pin = 96 PD01 Pin = 97 PD02 Pin = 98 PD03 Pin = 99 PD04 Pin = 100 PD05 Pin = 101 PD06 Pin = 102 PD07 Pin = 103 PD08 Pin = 104 // peripherals: TCC0 channel 1 PD09 Pin = 105 // peripherals: TCC0 channel 2 PD10 Pin = 106 // peripherals: TCC0 channel 3 PD11 Pin = 107 // peripherals: TCC0 channel 4 PD12 Pin = 108 // peripherals: TCC0 channel 5 PD13 Pin = 109 // peripherals: TCC0 channel 6 PD14 Pin = 110 PD15 Pin = 111 PD16 Pin = 112 PD17 Pin = 113 PD18 Pin = 114 PD19 Pin = 115 PD20 Pin = 116 // peripherals: TCC1 channel 0 PD21 Pin = 117 // peripherals: TCC1 channel 1 PD22 Pin = 118 PD23 Pin = 119 PD24 Pin = 120 PD25 Pin = 121 PD26 Pin = 122 PD27 Pin = 123 PD28 Pin = 124 PD29 Pin = 125 PD30 Pin = 126 PD31 Pin = 127 ) const ( pinPadMapSERCOM0Pad0 uint16 = 0x1000 pinPadMapSERCOM1Pad0 uint16 = 0x2000 pinPadMapSERCOM2Pad0 uint16 = 0x3000 pinPadMapSERCOM3Pad0 uint16 = 0x4000 pinPadMapSERCOM4Pad0 uint16 = 0x5000 pinPadMapSERCOM5Pad0 uint16 = 0x6000 pinPadMapSERCOM6Pad0 uint16 = 0x7000 pinPadMapSERCOM7Pad0 uint16 = 0x8000 pinPadMapSERCOM0Pad2 uint16 = 0x1200 pinPadMapSERCOM1Pad2 uint16 = 0x2200 pinPadMapSERCOM2Pad2 uint16 = 0x3200 pinPadMapSERCOM3Pad2 uint16 = 0x4200 pinPadMapSERCOM4Pad2 uint16 = 0x5200 pinPadMapSERCOM5Pad2 uint16 = 0x6200 pinPadMapSERCOM6Pad2 uint16 = 0x7200 pinPadMapSERCOM7Pad2 uint16 = 0x8200 pinPadMapSERCOM0AltPad0 uint16 = 0x0010 pinPadMapSERCOM1AltPad0 uint16 = 0x0020 pinPadMapSERCOM2AltPad0 uint16 = 0x0030 pinPadMapSERCOM3AltPad0 uint16 = 0x0040 pinPadMapSERCOM4AltPad0 uint16 = 0x0050 pinPadMapSERCOM5AltPad0 uint16 = 0x0060 pinPadMapSERCOM6AltPad0 uint16 = 0x0070 pinPadMapSERCOM7AltPad0 uint16 = 0x0080 pinPadMapSERCOM0AltPad1 uint16 = 0x0011 pinPadMapSERCOM1AltPad1 uint16 = 0x0021 pinPadMapSERCOM2AltPad1 uint16 = 0x0031 pinPadMapSERCOM3AltPad1 uint16 = 0x0041 pinPadMapSERCOM4AltPad1 uint16 = 0x0051 pinPadMapSERCOM5AltPad1 uint16 = 0x0061 pinPadMapSERCOM6AltPad1 uint16 = 0x0071 pinPadMapSERCOM7AltPad1 uint16 = 0x0081 pinPadMapSERCOM0AltPad2 uint16 = 0x0012 pinPadMapSERCOM1AltPad2 uint16 = 0x0022 pinPadMapSERCOM2AltPad2 uint16 = 0x0032 pinPadMapSERCOM3AltPad2 uint16 = 0x0042 pinPadMapSERCOM4AltPad2 uint16 = 0x0052 pinPadMapSERCOM5AltPad2 uint16 = 0x0062 pinPadMapSERCOM6AltPad2 uint16 = 0x0072 pinPadMapSERCOM7AltPad2 uint16 = 0x0082 ) // pinPadMapping lists which pins have which SERCOMs attached to them. // The encoding is rather dense, with each uint16 encoding two pins and both // SERCOM and SERCOM-ALT. // // Observations: // - There are eight SERCOMs. Those SERCOM numbers can be encoded in 4 bits. // - Even pad numbers are usually on even pins, and odd pad numbers are usually // on odd pins. The exception is SERCOM-ALT, which sometimes swaps pad 0 and 1. // With that, there is still an invariant that the pad number for an odd pin is // the pad number for the corresponding even pin with the low bit toggled. // - Pin pads come in pairs. If PA00 has pad 0, then PA01 has pad 1. // // With this information, we can encode SERCOM pin/pad numbers much more // efficiently. Due to pads coming in pairs, we can ignore half the pins: the // information for an odd pin can be calculated easily from the preceding even // pin. // // Each word below is split in two bytes. The 8 high bytes are for SERCOM and // the 8 low bits are for SERCOM-ALT. Of each byte, the 4 high bits encode the // SERCOM + 1 while the two low bits encodes the pad number (the pad number for // the odd pin can be trivially calculated by toggling the low bit of the pad // number). It encodes SERCOM + 1 instead of just the SERCOM number, to make it // easy to check whether a nibble is set at all. // // Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/60001507E.pdf var pinPadMapping = [64]uint16{ // page 32 PA00 / 2: 0 | pinPadMapSERCOM1AltPad0, // page 33 PB08 / 2: 0 | pinPadMapSERCOM4AltPad0, PA04 / 2: 0 | pinPadMapSERCOM0AltPad0, PA06 / 2: 0 | pinPadMapSERCOM0AltPad2, PC04 / 2: pinPadMapSERCOM6Pad0 | 0, PC06 / 2: pinPadMapSERCOM6Pad2 | 0, PA08 / 2: pinPadMapSERCOM0Pad0 | pinPadMapSERCOM2AltPad1, PA10 / 2: pinPadMapSERCOM0Pad2 | pinPadMapSERCOM2AltPad2, PB10 / 2: 0 | pinPadMapSERCOM4AltPad2, PB12 / 2: pinPadMapSERCOM4Pad0 | 0, PB14 / 2: pinPadMapSERCOM4Pad2 | 0, PD08 / 2: pinPadMapSERCOM7Pad0 | pinPadMapSERCOM6AltPad1, PD10 / 2: pinPadMapSERCOM7Pad2 | pinPadMapSERCOM6AltPad2, PC10 / 2: pinPadMapSERCOM6Pad2 | pinPadMapSERCOM7AltPad2, // page 34 PC12 / 2: pinPadMapSERCOM7Pad0 | pinPadMapSERCOM6AltPad1, PC14 / 2: pinPadMapSERCOM7Pad2 | pinPadMapSERCOM6AltPad2, PA12 / 2: pinPadMapSERCOM2Pad0 | pinPadMapSERCOM4AltPad1, PA14 / 2: pinPadMapSERCOM2Pad2 | pinPadMapSERCOM4AltPad2, PA16 / 2: pinPadMapSERCOM1Pad0 | pinPadMapSERCOM3AltPad1, PA18 / 2: pinPadMapSERCOM1Pad2 | pinPadMapSERCOM3AltPad2, PC16 / 2: pinPadMapSERCOM6Pad0 | pinPadMapSERCOM0AltPad1, PC18 / 2: pinPadMapSERCOM6Pad2 | pinPadMapSERCOM0AltPad2, PC22 / 2: pinPadMapSERCOM1Pad0 | pinPadMapSERCOM3AltPad1, PD20 / 2: pinPadMapSERCOM1Pad2 | pinPadMapSERCOM3AltPad2, PB16 / 2: pinPadMapSERCOM5Pad0 | 0, PB18 / 2: pinPadMapSERCOM5Pad2 | pinPadMapSERCOM7AltPad2, // page 35 PB20 / 2: pinPadMapSERCOM3Pad0 | pinPadMapSERCOM7AltPad1, PA20 / 2: pinPadMapSERCOM5Pad2 | pinPadMapSERCOM3AltPad2, PA22 / 2: pinPadMapSERCOM3Pad0 | pinPadMapSERCOM5AltPad1, PA24 / 2: pinPadMapSERCOM3Pad2 | pinPadMapSERCOM5AltPad2, PB22 / 2: pinPadMapSERCOM1Pad2 | pinPadMapSERCOM5AltPad2, PB24 / 2: pinPadMapSERCOM0Pad0 | pinPadMapSERCOM2AltPad1, PB26 / 2: pinPadMapSERCOM2Pad0 | pinPadMapSERCOM4AltPad1, PB28 / 2: pinPadMapSERCOM2Pad2 | pinPadMapSERCOM4AltPad2, PC24 / 2: pinPadMapSERCOM0Pad2 | pinPadMapSERCOM2AltPad2, //PC26 / 2: pinPadMapSERCOM1Pad1 | 0, // note: PC26 doesn't support SERCOM, but PC27 does //PC28 / 2: pinPadMapSERCOM1Pad1 | 0, // note: PC29 doesn't exist in the datasheet? PA30 / 2: 0 | pinPadMapSERCOM1AltPad2, // page 36 PB30 / 2: 0 | pinPadMapSERCOM5AltPad1, PB00 / 2: 0 | pinPadMapSERCOM5AltPad2, PB02 / 2: 0 | pinPadMapSERCOM5AltPad0, } // findPinPadMapping looks up the pad number and the pinmode for a given pin and // SERCOM number. The result can either be SERCOM, SERCOM-ALT, or "not found" // (indicated by returning ok=false). The pad number is returned to calculate // the DOPO/DIPO bitfields of the various serial peripherals. func findPinPadMapping(sercom uint8, pin Pin) (pinMode PinMode, pad uint32, ok bool) { if int(pin)/2 >= len(pinPadMapping) { // This is probably NoPin, for which no mapping is available. return } bytes := pinPadMapping[pin/2] upper := byte(bytes >> 8) lower := byte(bytes & 0xff) if upper != 0 { // SERCOM if (upper>>4)-1 == sercom { pinMode = PinSERCOM pad |= uint32(upper % 4) ok = true } } if lower != 0 { // SERCOM-ALT if (lower>>4)-1 == sercom { pinMode = PinSERCOMAlt pad |= uint32(lower % 4) ok = true } } if ok { // If the pin is uneven, toggle the lowest bit of the pad number. if pin&1 != 0 { pad ^= 1 } } return } // SetInterrupt sets an interrupt to be executed when a particular pin changes // state. The pin should already be configured as an input, including a pull up // or down if no external pull is provided. // // This call will replace a previously set callback on this pin. You can pass a // nil func to unset the pin change interrupt. If you do so, the change // parameter is ignored and can be set to any value (such as 0). func (p Pin) SetInterrupt(change PinChange, callback func(Pin)) error { // Most pins follow a common pattern where the EXTINT value is the pin // number modulo 16. However, there are a few exceptions, as you can see // below. extint := uint8(0) switch p { case PA08: // Connected to NMI. This is not currently supported. return ErrInvalidInputPin case PB26: extint = 12 case PB27: extint = 13 case PB28: extint = 14 case PB29: extint = 15 case PC07: extint = 9 case PD08: extint = 3 case PD09: extint = 4 case PD10: extint = 5 case PD11: extint = 6 case PD12: extint = 7 case PD20: extint = 10 case PD21: extint = 11 default: // All other pins follow a normal pattern. extint = uint8(p) % 16 } if callback == nil { // Disable this pin interrupt (if it was enabled). sam.EIC.INTENCLR.Set(1 << extint) if pinCallbacks[extint] != nil { pinCallbacks[extint] = nil } return nil } if pinCallbacks[extint] != nil { // The pin was already configured. // To properly re-configure a pin, unset it first and set a new // configuration. return ErrNoPinChangeChannel } pinCallbacks[extint] = callback interruptPins[extint] = p if !sam.EIC.CTRLA.HasBits(sam.EIC_CTRLA_ENABLE) { // EIC peripheral has not yet been initialized. Initialize it now. // The EIC needs two clocks: CLK_EIC_APB and GCLK_EIC. CLK_EIC_APB is // enabled by default, so doesn't have to be re-enabled. The other is // required for detecting edges and must be enabled manually. sam.GCLK.PCHCTRL[4].Set((sam.GCLK_PCHCTRL_GEN_GCLK0 << sam.GCLK_PCHCTRL_GEN_Pos) | sam.GCLK_PCHCTRL_CHEN) // should not be necessary (CLKCTRL is not synchronized) for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL_GCLK0 << sam.GCLK_SYNCBUSY_GENCTRL_Pos) { } } // CONFIG register is enable-protected, so disable EIC. sam.EIC.CTRLA.ClearBits(sam.EIC_CTRLA_ENABLE) // Configure this pin. Set the 4 bits of the EIC.CONFIGx register to the // sense value (filter bit set to 0, sense bits set to the change value). addr := &sam.EIC.CONFIG[0] if extint >= 8 { addr = &sam.EIC.CONFIG[1] } pos := (extint % 8) * 4 // bit position in register addr.ReplaceBits(uint32(change), 0xf, pos) // Enable external interrupt for this pin. sam.EIC.INTENSET.Set(1 << extint) sam.EIC.CTRLA.Set(sam.EIC_CTRLA_ENABLE) for sam.EIC.SYNCBUSY.HasBits(sam.EIC_SYNCBUSY_ENABLE) { } // Set the PMUXEN flag, while keeping the INEN and PULLEN flags (if they // were set before). This avoids clearing the pin pull mode while // configuring the pin interrupt. p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN | (p.getPinCfg() & (sam.PORT_GROUP_PINCFG_INEN | sam.PORT_GROUP_PINCFG_PULLEN))) if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (0 << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (0 << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } handleEICInterrupt := func(interrupt.Interrupt) { flags := sam.EIC.INTFLAG.Get() sam.EIC.INTFLAG.Set(flags) // clear interrupt for i := uint(0); i < 16; i++ { // there are 16 channels if flags&(1<>pin_in_group)&1 > 0 } // Toggle switches an output pin from low to high or from high to low. // Warning: only use this on an output pin! func (p Pin) Toggle() { group, pin_in_group := p.getPinGrouping() sam.PORT.GROUP[group].OUTTGL.Set(1 << pin_in_group) } // Configure this pin with the given configuration. func (p Pin) Configure(config PinConfig) { group, pin_in_group := p.getPinGrouping() switch config.Mode { case PinOutput: sam.PORT.GROUP[group].DIRSET.Set(1 << pin_in_group) // output is also set to input enable so pin can read back its own value p.setPinCfg(sam.PORT_GROUP_PINCFG_INEN) case PinInput: sam.PORT.GROUP[group].DIRCLR.Set(1 << pin_in_group) p.setPinCfg(sam.PORT_GROUP_PINCFG_INEN) case PinInputPulldown: sam.PORT.GROUP[group].DIRCLR.Set(1 << pin_in_group) sam.PORT.GROUP[group].OUTCLR.Set(1 << pin_in_group) p.setPinCfg(sam.PORT_GROUP_PINCFG_INEN | sam.PORT_GROUP_PINCFG_PULLEN) case PinInputPullup: sam.PORT.GROUP[group].DIRCLR.Set(1 << pin_in_group) sam.PORT.GROUP[group].OUTSET.Set(1 << pin_in_group) p.setPinCfg(sam.PORT_GROUP_PINCFG_INEN | sam.PORT_GROUP_PINCFG_PULLEN) case PinSERCOM: if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (uint8(PinSERCOM) << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (uint8(PinSERCOM) << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } // enable port config p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN | sam.PORT_GROUP_PINCFG_DRVSTR | sam.PORT_GROUP_PINCFG_INEN) case PinSERCOMAlt: if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (uint8(PinSERCOMAlt) << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (uint8(PinSERCOMAlt) << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } // enable port config p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN | sam.PORT_GROUP_PINCFG_DRVSTR) case PinCom: if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (uint8(PinCom) << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (uint8(PinCom) << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } // enable port config p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN) case PinAnalog: if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (uint8(PinAnalog) << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (uint8(PinAnalog) << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } // enable port config p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN | sam.PORT_GROUP_PINCFG_DRVSTR) case PinSDHC: if p&1 > 0 { // odd pin, so save the even pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk p.setPMux(val | (uint8(PinSDHC) << sam.PORT_GROUP_PMUX_PMUXO_Pos)) } else { // even pin, so save the odd pins val := p.getPMux() & sam.PORT_GROUP_PMUX_PMUXO_Msk p.setPMux(val | (uint8(PinSDHC) << sam.PORT_GROUP_PMUX_PMUXE_Pos)) } // enable port config p.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN) } } // getPMux returns the value for the correct PMUX register for this pin. func (p Pin) getPMux() uint8 { group, pin_in_group := p.getPinGrouping() return sam.PORT.GROUP[group].PMUX[pin_in_group>>1].Get() } // setPMux sets the value for the correct PMUX register for this pin. func (p Pin) setPMux(val uint8) { group, pin_in_group := p.getPinGrouping() sam.PORT.GROUP[group].PMUX[pin_in_group>>1].Set(val) } // getPinCfg returns the value for the correct PINCFG register for this pin. func (p Pin) getPinCfg() uint8 { group, pin_in_group := p.getPinGrouping() return sam.PORT.GROUP[group].PINCFG[pin_in_group].Get() } // setPinCfg sets the value for the correct PINCFG register for this pin. func (p Pin) setPinCfg(val uint8) { group, pin_in_group := p.getPinGrouping() sam.PORT.GROUP[group].PINCFG[pin_in_group].Set(val) } // getPinGrouping calculates the gpio group and pin id from the pin number. // Pins are split into groups of 32, and each group has its own set of // control registers. func (p Pin) getPinGrouping() (uint8, uint8) { group := uint8(p) >> 5 pin_in_group := uint8(p) & 0x1f return group, pin_in_group } // InitADC initializes the ADC. func InitADC() { // ADC Bias Calibration // NVMCTRL_SW0 0x00800080 // #define ADC0_FUSES_BIASCOMP_ADDR NVMCTRL_SW0 // #define ADC0_FUSES_BIASCOMP_Pos 2 /**< \brief (NVMCTRL_SW0) ADC Comparator Scaling */ // #define ADC0_FUSES_BIASCOMP_Msk (_Ul(0x7) << ADC0_FUSES_BIASCOMP_Pos) // #define ADC0_FUSES_BIASCOMP(value) (ADC0_FUSES_BIASCOMP_Msk & ((value) << ADC0_FUSES_BIASCOMP_Pos)) // #define ADC0_FUSES_BIASR2R_ADDR NVMCTRL_SW0 // #define ADC0_FUSES_BIASR2R_Pos 8 /**< \brief (NVMCTRL_SW0) ADC Bias R2R ampli scaling */ // #define ADC0_FUSES_BIASR2R_Msk (_Ul(0x7) << ADC0_FUSES_BIASR2R_Pos) // #define ADC0_FUSES_BIASR2R(value) (ADC0_FUSES_BIASR2R_Msk & ((value) << ADC0_FUSES_BIASR2R_Pos)) // #define ADC0_FUSES_BIASREFBUF_ADDR NVMCTRL_SW0 // #define ADC0_FUSES_BIASREFBUF_Pos 5 /**< \brief (NVMCTRL_SW0) ADC Bias Reference Buffer Scaling */ // #define ADC0_FUSES_BIASREFBUF_Msk (_Ul(0x7) << ADC0_FUSES_BIASREFBUF_Pos) // #define ADC0_FUSES_BIASREFBUF(value) (ADC0_FUSES_BIASREFBUF_Msk & ((value) << ADC0_FUSES_BIASREFBUF_Pos)) // #define ADC1_FUSES_BIASCOMP_ADDR NVMCTRL_SW0 // #define ADC1_FUSES_BIASCOMP_Pos 16 /**< \brief (NVMCTRL_SW0) ADC Comparator Scaling */ // #define ADC1_FUSES_BIASCOMP_Msk (_Ul(0x7) << ADC1_FUSES_BIASCOMP_Pos) // #define ADC1_FUSES_BIASCOMP(value) (ADC1_FUSES_BIASCOMP_Msk & ((value) << ADC1_FUSES_BIASCOMP_Pos)) // #define ADC1_FUSES_BIASR2R_ADDR NVMCTRL_SW0 // #define ADC1_FUSES_BIASR2R_Pos 22 /**< \brief (NVMCTRL_SW0) ADC Bias R2R ampli scaling */ // #define ADC1_FUSES_BIASR2R_Msk (_Ul(0x7) << ADC1_FUSES_BIASR2R_Pos) // #define ADC1_FUSES_BIASR2R(value) (ADC1_FUSES_BIASR2R_Msk & ((value) << ADC1_FUSES_BIASR2R_Pos)) // #define ADC1_FUSES_BIASREFBUF_ADDR NVMCTRL_SW0 // #define ADC1_FUSES_BIASREFBUF_Pos 19 /**< \brief (NVMCTRL_SW0) ADC Bias Reference Buffer Scaling */ // #define ADC1_FUSES_BIASREFBUF_Msk (_Ul(0x7) << ADC1_FUSES_BIASREFBUF_Pos) // #define ADC1_FUSES_BIASREFBUF(value) (ADC1_FUSES_BIASREFBUF_Msk & ((value) << ADC1_FUSES_BIASREFBUF_Pos)) adcFuse := *(*uint32)(unsafe.Pointer(uintptr(0x00800080))) // uint32_t biascomp = (*((uint32_t *)ADC0_FUSES_BIASCOMP_ADDR) & ADC0_FUSES_BIASCOMP_Msk) >> ADC0_FUSES_BIASCOMP_Pos; biascomp := (adcFuse & uint32(0x7<<2)) //>> 2 // uint32_t biasr2r = (*((uint32_t *)ADC0_FUSES_BIASR2R_ADDR) & ADC0_FUSES_BIASR2R_Msk) >> ADC0_FUSES_BIASR2R_Pos; biasr2r := (adcFuse & uint32(0x7<<8)) //>> 8 // uint32_t biasref = (*((uint32_t *)ADC0_FUSES_BIASREFBUF_ADDR) & ADC0_FUSES_BIASREFBUF_Msk) >> ADC0_FUSES_BIASREFBUF_Pos; biasref := (adcFuse & uint32(0x7<<5)) //>> 5 // calibrate ADC0 sam.ADC0.CALIB.Set(uint16(biascomp | biasr2r | biasref)) // biascomp = (*((uint32_t *)ADC1_FUSES_BIASCOMP_ADDR) & ADC1_FUSES_BIASCOMP_Msk) >> ADC1_FUSES_BIASCOMP_Pos; biascomp = (adcFuse & uint32(0x7<<16)) //>> 16 // biasr2r = (*((uint32_t *)ADC1_FUSES_BIASR2R_ADDR) & ADC1_FUSES_BIASR2R_Msk) >> ADC1_FUSES_BIASR2R_Pos; biasr2r = (adcFuse & uint32(0x7<<22)) //>> 22 // biasref = (*((uint32_t *)ADC1_FUSES_BIASREFBUF_ADDR) & ADC1_FUSES_BIASREFBUF_Msk) >> ADC1_FUSES_BIASREFBUF_Pos; biasref = (adcFuse & uint32(0x7<<19)) //>> 19 // calibrate ADC1 sam.ADC1.CALIB.Set(uint16((biascomp | biasr2r | biasref) >> 16)) } // Configure configures a ADCPin to be able to be used to read data. func (a ADC) Configure(config ADCConfig) { for _, adc := range []*sam.ADC_Type{sam.ADC0, sam.ADC1} { for adc.SYNCBUSY.HasBits(sam.ADC_SYNCBUSY_CTRLB) { } // wait for sync // Averaging (see datasheet table in AVGCTRL register description) var resolution uint32 = sam.ADC_CTRLB_RESSEL_16BIT var samples uint32 switch config.Samples { case 2: samples = sam.ADC_AVGCTRL_SAMPLENUM_2 case 4: samples = sam.ADC_AVGCTRL_SAMPLENUM_4 case 8: samples = sam.ADC_AVGCTRL_SAMPLENUM_8 case 16: samples = sam.ADC_AVGCTRL_SAMPLENUM_16 case 32: samples = sam.ADC_AVGCTRL_SAMPLENUM_32 case 64: samples = sam.ADC_AVGCTRL_SAMPLENUM_64 case 128: samples = sam.ADC_AVGCTRL_SAMPLENUM_128 case 256: samples = sam.ADC_AVGCTRL_SAMPLENUM_256 case 512: samples = sam.ADC_AVGCTRL_SAMPLENUM_512 case 1024: samples = sam.ADC_AVGCTRL_SAMPLENUM_1024 default: // 1 sample only (no oversampling nor averaging), adjusting result by 0 // Resolutions less than 16 bits only make sense when sampling only // once. Resulting ADC values become erratic when using both // multi-sampling and less than 16 bits of resolution. samples = sam.ADC_AVGCTRL_SAMPLENUM_1 switch config.Resolution { case 8: resolution = sam.ADC_CTRLB_RESSEL_8BIT case 10: resolution = sam.ADC_CTRLB_RESSEL_10BIT case 12: resolution = sam.ADC_CTRLB_RESSEL_12BIT case 16: resolution = sam.ADC_CTRLB_RESSEL_16BIT default: resolution = sam.ADC_CTRLB_RESSEL_12BIT } } adc.AVGCTRL.Set(uint8(samples<> sam.ADC_CTRLB_RESSEL_Pos { case sam.ADC_CTRLB_RESSEL_8BIT: val = val << 8 case sam.ADC_CTRLB_RESSEL_10BIT: val = val << 6 case sam.ADC_CTRLB_RESSEL_12BIT: val = val << 4 case sam.ADC_CTRLB_RESSEL_16BIT: // Adjust for multiple samples. This is only configured when the // resolution is 16 bits. switch (bus.AVGCTRL.Get() & sam.ADC_AVGCTRL_SAMPLENUM_Msk) >> sam.ADC_AVGCTRL_SAMPLENUM_Pos { case sam.ADC_AVGCTRL_SAMPLENUM_1: val <<= 4 case sam.ADC_AVGCTRL_SAMPLENUM_2: val <<= 3 case sam.ADC_AVGCTRL_SAMPLENUM_4: val <<= 2 case sam.ADC_AVGCTRL_SAMPLENUM_8: val <<= 1 default: // These values are all shifted by the hardware so they fit exactly // in a 16-bit integer, so they don't need to be shifted here. } } return val } func (a ADC) getADCBus() *sam.ADC_Type { if (a.Pin >= PB04 && a.Pin <= PB07) || (a.Pin >= PC00) { return sam.ADC1 } return sam.ADC0 } func (a ADC) getADCChannel() uint8 { switch a.Pin { case PA02: return 0 case PB08: return 2 case PB09: return 3 case PA04: return 4 case PA05: return 5 case PA06: return 6 case PA07: return 7 case PB00: return 12 case PB01: return 13 case PB02: return 14 case PB03: return 15 case PA09: return 17 case PA11: return 19 case PB04: return 6 case PB05: return 7 case PB06: return 8 case PB07: return 9 case PC00: return 10 case PC01: return 11 case PC02: return 4 case PC03: return 5 case PC30: return 12 case PC31: return 13 case PD00: return 14 case PD01: return 15 default: panic("Invalid ADC pin") } } // UART on the SAMD51. type UART struct { Buffer *RingBuffer Bus *sam.SERCOM_USART_INT_Type SERCOM uint8 Interrupt interrupt.Interrupt // RXC interrupt } var ( sercomUSART0 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM0_USART_INT, SERCOM: 0} sercomUSART1 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM1_USART_INT, SERCOM: 1} sercomUSART2 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM2_USART_INT, SERCOM: 2} sercomUSART3 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM3_USART_INT, SERCOM: 3} sercomUSART4 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM4_USART_INT, SERCOM: 4} sercomUSART5 = UART{Buffer: NewRingBuffer(), Bus: sam.SERCOM5_USART_INT, SERCOM: 5} ) func init() { sercomUSART0.Interrupt = interrupt.New(sam.IRQ_SERCOM0_2, sercomUSART0.handleInterrupt) sercomUSART1.Interrupt = interrupt.New(sam.IRQ_SERCOM1_2, sercomUSART1.handleInterrupt) sercomUSART2.Interrupt = interrupt.New(sam.IRQ_SERCOM2_2, sercomUSART2.handleInterrupt) sercomUSART3.Interrupt = interrupt.New(sam.IRQ_SERCOM3_2, sercomUSART3.handleInterrupt) sercomUSART4.Interrupt = interrupt.New(sam.IRQ_SERCOM4_2, sercomUSART4.handleInterrupt) sercomUSART5.Interrupt = interrupt.New(sam.IRQ_SERCOM5_2, sercomUSART5.handleInterrupt) } const ( sampleRate16X = 16 lsbFirst = 1 ) // Configure the UART. func (uart *UART) Configure(config UARTConfig) error { // Default baud rate to 115200. if config.BaudRate == 0 { config.BaudRate = 115200 } // determine pins if config.TX == 0 && config.RX == 0 { // use default pins config.TX = UART_TX_PIN config.RX = UART_RX_PIN } // Determine transmit pinout. txPinMode, txPad, ok := findPinPadMapping(uart.SERCOM, config.TX) if !ok { return ErrInvalidOutputPin } var txPinOut uint32 // See CTRLA.RXPO bits of the SERCOM USART peripheral (page 945-946) for how // pads are mapped to pinout values. switch txPad { case 0: txPinOut = 0 default: // TODO: flow control (RTS/CTS) return ErrInvalidOutputPin } // Determine receive pinout. rxPinMode, rxPad, ok := findPinPadMapping(uart.SERCOM, config.RX) if !ok { return ErrInvalidInputPin } // As you can see in the CTRLA.RXPO bits of the SERCOM USART peripheral // (page 945), input pins are mapped directly. rxPinOut := rxPad // configure pins config.TX.Configure(PinConfig{Mode: txPinMode}) config.RX.Configure(PinConfig{Mode: rxPinMode}) // reset SERCOM uart.Bus.CTRLA.SetBits(sam.SERCOM_USART_INT_CTRLA_SWRST) for uart.Bus.CTRLA.HasBits(sam.SERCOM_USART_INT_CTRLA_SWRST) || uart.Bus.SYNCBUSY.HasBits(sam.SERCOM_USART_INT_SYNCBUSY_SWRST) { } // set UART mode/sample rate // SERCOM_USART_CTRLA_MODE(mode) | // SERCOM_USART_CTRLA_SAMPR(sampleRate); // sam.SERCOM_USART_CTRLA_MODE_USART_INT_CLK = 1? uart.Bus.CTRLA.Set((1 << sam.SERCOM_USART_INT_CTRLA_MODE_Pos) | (1 << sam.SERCOM_USART_INT_CTRLA_SAMPR_Pos)) // sample rate of 16x // set clock setSERCOMClockGenerator(uart.SERCOM, sam.GCLK_PCHCTRL_GEN_GCLK1) // Set baud rate uart.SetBaudRate(config.BaudRate) // setup UART frame // SERCOM_USART_CTRLA_FORM( (parityMode == SERCOM_NO_PARITY ? 0 : 1) ) | // dataOrder << SERCOM_USART_CTRLA_DORD_Pos; uart.Bus.CTRLA.SetBits((0 << sam.SERCOM_USART_INT_CTRLA_FORM_Pos) | // no parity (lsbFirst << sam.SERCOM_USART_INT_CTRLA_DORD_Pos)) // data order // set UART stop bits/parity // SERCOM_USART_CTRLB_CHSIZE(charSize) | // nbStopBits << SERCOM_USART_CTRLB_SBMODE_Pos | // (parityMode == SERCOM_NO_PARITY ? 0 : parityMode) << SERCOM_USART_CTRLB_PMODE_Pos; //If no parity use default value uart.Bus.CTRLB.SetBits((0 << sam.SERCOM_USART_INT_CTRLB_CHSIZE_Pos) | // 8 bits is 0 (0 << sam.SERCOM_USART_INT_CTRLB_SBMODE_Pos) | // 1 stop bit is zero (0 << sam.SERCOM_USART_INT_CTRLB_PMODE_Pos)) // no parity // set UART pads. This is not same as pins... // SERCOM_USART_CTRLA_TXPO(txPad) | // SERCOM_USART_CTRLA_RXPO(rxPad); uart.Bus.CTRLA.SetBits((txPinOut << sam.SERCOM_USART_INT_CTRLA_TXPO_Pos) | (rxPinOut << sam.SERCOM_USART_INT_CTRLA_RXPO_Pos)) // Enable Transceiver and Receiver //sercom->USART.CTRLB.reg |= SERCOM_USART_CTRLB_TXEN | SERCOM_USART_CTRLB_RXEN ; uart.Bus.CTRLB.SetBits(sam.SERCOM_USART_INT_CTRLB_TXEN | sam.SERCOM_USART_INT_CTRLB_RXEN) // Enable USART1 port. // sercom->USART.CTRLA.bit.ENABLE = 0x1u; uart.Bus.CTRLA.SetBits(sam.SERCOM_USART_INT_CTRLA_ENABLE) for uart.Bus.SYNCBUSY.HasBits(sam.SERCOM_USART_INT_SYNCBUSY_ENABLE) { } // setup interrupt on receive uart.Bus.INTENSET.Set(sam.SERCOM_USART_INT_INTENSET_RXC) // Enable RX IRQ. // This is a small note at the bottom of the NVIC section of the datasheet: // > The integer number specified in the source refers to the respective bit // > position in the INTFLAG register of respective peripheral. // Therefore, if we only need to listen to the RXC interrupt source (in bit // position 2), we only need interrupt source 2 for this SERCOM device. uart.Interrupt.Enable() return nil } // SetBaudRate sets the communication speed for the UART. func (uart *UART) SetBaudRate(br uint32) { // Asynchronous fractional mode (Table 24-2 in datasheet) // BAUD = fref / (sampleRateValue * fbaud) // (multiply by 8, to calculate fractional piece) // uint32_t baudTimes8 = (SystemCoreClock * 8) / (16 * baudrate); baud := (SERCOM_FREQ_REF * 8) / (sampleRate16X * br) // sercom->USART.BAUD.FRAC.FP = (baudTimes8 % 8); // sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8); uart.Bus.BAUD.Set(uint16(((baud % 8) << sam.SERCOM_USART_INT_BAUD_FRAC_MODE_FP_Pos) | ((baud / 8) << sam.SERCOM_USART_INT_BAUD_FRAC_MODE_BAUD_Pos))) } // WriteByte writes a byte of data to the UART. func (uart *UART) writeByte(c byte) error { // wait until ready to receive for !uart.Bus.INTFLAG.HasBits(sam.SERCOM_USART_INT_INTFLAG_DRE) { } uart.Bus.DATA.Set(uint32(c)) return nil } func (uart *UART) flush() {} func (uart *UART) handleInterrupt(interrupt.Interrupt) { // should reset IRQ uart.Receive(byte((uart.Bus.DATA.Get() & 0xFF))) uart.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INT_INTFLAG_RXC) } // I2C on the SAMD51. type I2C struct { Bus *sam.SERCOM_I2CM_Type SERCOM uint8 } // I2CConfig is used to store config info for I2C. type I2CConfig struct { Frequency uint32 SCL Pin SDA Pin } const ( // SERCOM_FREQ_REF is always reference frequency on SAMD51 regardless of CPU speed. SERCOM_FREQ_REF = 48000000 SERCOM_FREQ_REF_GCLK0 = 120000000 // Default rise time in nanoseconds, based on 4.7K ohm pull up resistors riseTimeNanoseconds = 125 // wire bus states wireUnknownState = 0 wireIdleState = 1 wireOwnerState = 2 wireBusyState = 3 // wire commands wireCmdNoAction = 0 wireCmdRepeatStart = 1 wireCmdRead = 2 wireCmdStop = 3 ) const i2cTimeout = 28000 // about 210us // Configure is intended to setup the I2C interface. func (i2c *I2C) Configure(config I2CConfig) error { // Default I2C bus speed is 100 kHz. if config.Frequency == 0 { config.Frequency = 100 * KHz } // Use default I2C pins if not set. if config.SDA == 0 && config.SCL == 0 { config.SDA = SDA_PIN config.SCL = SCL_PIN } sclPinMode, sclPad, ok := findPinPadMapping(i2c.SERCOM, config.SCL) if !ok || sclPad != 1 { // SCL must be on pad 1, according to section 36.4 of the datasheet. // Note: this is not an exhaustive test for I2C support on the pin: not // all pins support I2C. return ErrInvalidClockPin } sdaPinMode, sdaPad, ok := findPinPadMapping(i2c.SERCOM, config.SDA) if !ok || sdaPad != 0 { // SDA must be on pad 0, according to section 36.4 of the datasheet. // Note: this is not an exhaustive test for I2C support on the pin: not // all pins support I2C. return ErrInvalidDataPin } // reset SERCOM i2c.Bus.CTRLA.SetBits(sam.SERCOM_I2CM_CTRLA_SWRST) for i2c.Bus.CTRLA.HasBits(sam.SERCOM_I2CM_CTRLA_SWRST) || i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SWRST) { } // set clock setSERCOMClockGenerator(i2c.SERCOM, sam.GCLK_PCHCTRL_GEN_GCLK1) // Set i2c controller mode //SERCOM_I2CM_CTRLA_MODE( I2C_MASTER_OPERATION ) // sam.SERCOM_I2CM_CTRLA_MODE_I2C_MASTER = 5? i2c.Bus.CTRLA.Set(5 << sam.SERCOM_I2CM_CTRLA_MODE_Pos) // | i2c.SetBaudRate(config.Frequency) // Enable I2CM port. // sercom->USART.CTRLA.bit.ENABLE = 0x1u; i2c.Bus.CTRLA.SetBits(sam.SERCOM_I2CM_CTRLA_ENABLE) for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_ENABLE) { } // set bus idle mode i2c.Bus.STATUS.SetBits(wireIdleState << sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos) for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SYSOP) { } // enable pins config.SDA.Configure(PinConfig{Mode: sdaPinMode}) config.SCL.Configure(PinConfig{Mode: sclPinMode}) return nil } // SetBaudRate sets the communication speed for the I2C. func (i2c *I2C) SetBaudRate(br uint32) { // Synchronous arithmetic baudrate, via Adafruit SAMD51 implementation: // sercom->I2CM.BAUD.bit.BAUD = SERCOM_FREQ_REF / ( 2 * baudrate) - 1 ; baud := SERCOM_FREQ_REF/(2*br) - 1 i2c.Bus.BAUD.Set(baud) } // Tx does a single I2C transaction at the specified address. // It clocks out the given address, writes the bytes in w, reads back len(r) // bytes and stores them in r, and generates a stop condition on the bus. func (i2c *I2C) Tx(addr uint16, w, r []byte) error { var err error if len(w) != 0 { // send start/address for write i2c.sendAddress(addr, true) // wait until transmission complete timeout := i2cTimeout for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) { timeout-- if timeout == 0 { return errI2CWriteTimeout } } // ACK received (0: ACK, 1: NACK) if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) { return errI2CAckExpected } // write data for _, b := range w { err = i2c.WriteByte(b) if err != nil { return err } } err = i2c.signalStop() if err != nil { return err } } if len(r) != 0 { // send start/address for read i2c.sendAddress(addr, false) // wait transmission complete for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_SB) { // If the peripheral NACKS the address, the MB bit will be set. // In that case, send a stop condition and return error. if i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) { i2c.Bus.CTRLB.SetBits(wireCmdStop << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Stop condition return errI2CAckExpected } } // ACK received (0: ACK, 1: NACK) if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) { return errI2CAckExpected } // read first byte r[0] = i2c.readByte() for i := 1; i < len(r); i++ { // Send an ACK i2c.Bus.CTRLB.ClearBits(sam.SERCOM_I2CM_CTRLB_ACKACT) i2c.signalRead() // Read data and send the ACK r[i] = i2c.readByte() } // Send NACK to end transmission i2c.Bus.CTRLB.SetBits(sam.SERCOM_I2CM_CTRLB_ACKACT) err = i2c.signalStop() if err != nil { return err } } return nil } // WriteByte writes a single byte to the I2C bus. func (i2c *I2C) WriteByte(data byte) error { // Send data byte i2c.Bus.DATA.Set(data) // wait until transmission successful timeout := i2cTimeout for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) { // check for bus error if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_BUSERR) { return errI2CBusError } timeout-- if timeout == 0 { return errI2CWriteTimeout } } if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) { return errI2CAckExpected } return nil } // sendAddress sends the address and start signal func (i2c *I2C) sendAddress(address uint16, write bool) error { data := (address << 1) if !write { data |= 1 // set read flag } // wait until bus ready timeout := i2cTimeout for !i2c.Bus.STATUS.HasBits(wireIdleState< freqGCLK1 && uint32(uint8(baudRateGCLK0-1))+1 == baudRateGCLK0 { // Pick this 120MHz clock if it results in a better frequency after // division, and the baudRate value fits in the BAUD register. setSERCOMClockGenerator(spi.SERCOM, sam.GCLK_PCHCTRL_GEN_GCLK0) spi.Bus.BAUD.Set(uint8(baudRateGCLK0 - 1)) } else { // Use the 48MHz clock in other cases. setSERCOMClockGenerator(spi.SERCOM, sam.GCLK_PCHCTRL_GEN_GCLK1) spi.Bus.BAUD.Set(uint8(baudRateGCLK1 - 1)) } // Enable SPI port. spi.Bus.CTRLA.SetBits(sam.SERCOM_SPIM_CTRLA_ENABLE) for spi.Bus.SYNCBUSY.HasBits(sam.SERCOM_SPIM_SYNCBUSY_ENABLE) { } return nil } // Transfer writes/reads a single byte using the SPI interface. func (spi SPI) Transfer(w byte) (byte, error) { // write data spi.Bus.DATA.Set(uint32(w)) // wait for receive for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { } // return data return byte(spi.Bus.DATA.Get()), nil } // Tx handles read/write operation for SPI interface. Since SPI is a syncronous write/read // interface, there must always be the same number of bytes written as bytes read. // The Tx method knows about this, and offers a few different ways of calling it. // // This form sends the bytes in tx buffer, putting the resulting bytes read into the rx buffer. // Note that the tx and rx buffers must be the same size: // // spi.Tx(tx, rx) // // This form sends the tx buffer, ignoring the result. Useful for sending "commands" that return zeros // until all the bytes in the command packet have been received: // // spi.Tx(tx, nil) // // This form sends zeros, putting the result into the rx buffer. Good for reading a "result packet": // // spi.Tx(nil, rx) func (spi SPI) Tx(w, r []byte) error { switch { case w == nil: // read only, so write zero and read a result. spi.rx(r) case r == nil: // write only spi.tx(w) default: // write/read if len(w) != len(r) { return ErrTxInvalidSliceSize } spi.txrx(w, r) } return nil } func (spi SPI) tx(tx []byte) { for i := 0; i < len(tx); i++ { for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_DRE) { } spi.Bus.DATA.Set(uint32(tx[i])) } for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_TXC) { } // read to clear RXC register for spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { spi.Bus.DATA.Get() } } func (spi SPI) rx(rx []byte) { spi.Bus.DATA.Set(0) for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_DRE) { } for i := 1; i < len(rx); i++ { spi.Bus.DATA.Set(0) for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { } rx[i-1] = byte(spi.Bus.DATA.Get()) } for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { } rx[len(rx)-1] = byte(spi.Bus.DATA.Get()) } func (spi SPI) txrx(tx, rx []byte) { spi.Bus.DATA.Set(uint32(tx[0])) for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_DRE) { } for i := 1; i < len(rx); i++ { spi.Bus.DATA.Set(uint32(tx[i])) for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { } rx[i-1] = byte(spi.Bus.DATA.Get()) } for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) { } rx[len(rx)-1] = byte(spi.Bus.DATA.Get()) } // The QSPI peripheral on ATSAMD51 is only available on the following pins const ( QSPI_SCK = PB10 QSPI_CS = PB11 QSPI_DATA0 = PA08 QSPI_DATA1 = PA09 QSPI_DATA2 = PA10 QSPI_DATA3 = PA11 ) // TCC is one timer peripheral, which consists of a counter and multiple output // channels (that can be connected to actual pins). You can set the frequency // using SetPeriod, but only for all the channels in this timer peripheral at // once. type TCC sam.TCC_Type //go:inline func (tcc *TCC) timer() *sam.TCC_Type { return (*sam.TCC_Type)(tcc) } // Configure enables and configures this TCC. func (tcc *TCC) Configure(config PWMConfig) error { // Enable the TCC clock to be able to use the TCC. tcc.configureClock() // Disable timer (if it was enabled). This is necessary because // tcc.setPeriod may want to change the prescaler bits in CTRLA, which is // only allowed when the TCC is disabled. tcc.timer().CTRLA.ClearBits(sam.TCC_CTRLA_ENABLE) // Use "Normal PWM" (single-slope PWM) tcc.timer().WAVE.Set(sam.TCC_WAVE_WAVEGEN_NPWM) // Wait for synchronization of all changed registers. for tcc.timer().SYNCBUSY.Get() != 0 { } // Set the period and prescaler. err := tcc.setPeriod(config.Period, true) // Enable the timer. tcc.timer().CTRLA.SetBits(sam.TCC_CTRLA_ENABLE) // Wait for synchronization of all changed registers. for tcc.timer().SYNCBUSY.Get() != 0 { } // Return any error that might have occured in the tcc.setPeriod call. return err } // SetPeriod updates the period of this TCC peripheral. // To set a particular frequency, use the following formula: // // period = 1e9 / frequency // // If you use a period of 0, a period that works well for LEDs will be picked. // // SetPeriod will not change the prescaler, but also won't change the current // value in any of the channels. This means that you may need to update the // value for the particular channel. // // Note that you cannot pick any arbitrary period after the TCC peripheral has // been configured. If you want to switch between frequencies, pick the lowest // frequency (longest period) once when calling Configure and adjust the // frequency here as needed. func (tcc *TCC) SetPeriod(period uint64) error { return tcc.setPeriod(period, false) } // setPeriod sets the period of this TCC, possibly updating the prescaler as // well. The prescaler can only modified when the TCC is disabled, that is, in // the Configure function. func (tcc *TCC) setPeriod(period uint64, updatePrescaler bool) error { var top uint64 if period == 0 { // Make sure the TOP value is at 0xffff (enough for a 16-bit timer). top = 0xffff } else { // The formula below calculates the following formula, optimized: // period * (120e6 / 1e9) // This assumes that the chip is running from generic clock generator 0 // at 120MHz. top = period * 3 / 25 } maxTop := uint64(0xffff) if tcc.timer() == sam.TCC0 || tcc.timer() == sam.TCC1 { // Only TCC0 and TCC1 are 24-bit timers, the rest are 16-bit. maxTop = 0xffffff } if updatePrescaler { // This function was called during Configure(), with the timer disabled. // Note that updating the prescaler can only happen while the peripheral // is disabled. var prescaler uint32 switch { case top <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV1 case top/2 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV2 top = top / 2 case top/4 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV4 top = top / 4 case top/8 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV8 top = top / 8 case top/16 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV16 top = top / 16 case top/64 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV64 top = top / 64 case top/256 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV256 top = top / 256 case top/1024 <= maxTop: prescaler = sam.TCC_CTRLA_PRESCALER_DIV1024 top = top / 1024 default: return ErrPWMPeriodTooLong } tcc.timer().CTRLA.Set((tcc.timer().CTRLA.Get() &^ sam.TCC_CTRLA_PRESCALER_Msk) | (prescaler << sam.TCC_CTRLA_PRESCALER_Pos)) } else { // Do not update the prescaler, but use the already-configured // prescaler. This is the normal SetPeriod case, where the prescaler // must not be changed. prescaler := (tcc.timer().CTRLA.Get() & sam.TCC_CTRLA_PRESCALER_Msk) >> sam.TCC_CTRLA_PRESCALER_Pos switch prescaler { case sam.TCC_CTRLA_PRESCALER_DIV1: top /= 1 // no-op case sam.TCC_CTRLA_PRESCALER_DIV2: top /= 2 case sam.TCC_CTRLA_PRESCALER_DIV4: top /= 4 case sam.TCC_CTRLA_PRESCALER_DIV8: top /= 8 case sam.TCC_CTRLA_PRESCALER_DIV16: top /= 16 case sam.TCC_CTRLA_PRESCALER_DIV64: top /= 64 case sam.TCC_CTRLA_PRESCALER_DIV256: top /= 256 case sam.TCC_CTRLA_PRESCALER_DIV1024: top /= 1024 default: // unreachable } if top > maxTop { return ErrPWMPeriodTooLong } } // Set the period (the counter top). tcc.timer().PER.Set(uint32(top) - 1) // Wait for synchronization of CTRLA.PRESCALER and PER registers. for tcc.timer().SYNCBUSY.Get() != 0 { } return nil } // Top returns the current counter top, for use in duty cycle calculation. It // will only change with a call to Configure or SetPeriod, otherwise it is // constant. // // The value returned here is hardware dependent. In general, it's best to treat // it as an opaque value that can be divided by some number and passed to // tcc.Set (see tcc.Set for more information). func (tcc *TCC) Top() uint32 { return tcc.timer().PER.Get() + 1 } // Counter returns the current counter value of the timer in this TCC // peripheral. It may be useful for debugging. func (tcc *TCC) Counter() uint32 { tcc.timer().CTRLBSET.Set(sam.TCC_CTRLBSET_CMD_READSYNC << sam.TCC_CTRLBSET_CMD_Pos) for tcc.timer().SYNCBUSY.Get() != 0 { } return tcc.timer().COUNT.Get() } // Constants that encode a TCC number and WO number together in a single byte. const ( pinTCC0 = 1 << 4 // keep the value 0 usable as "no value" pinTCC1 = 2 << 4 pinTCC2 = 3 << 4 pinTCC3 = 4 << 4 pinTCC4 = 5 << 4 pinTCC0_0 = pinTCC0 | 0 pinTCC0_1 = pinTCC0 | 1 pinTCC0_2 = pinTCC0 | 2 pinTCC0_3 = pinTCC0 | 3 pinTCC0_4 = pinTCC0 | 4 pinTCC0_5 = pinTCC0 | 5 pinTCC0_6 = pinTCC0 | 6 pinTCC1_0 = pinTCC1 | 0 pinTCC1_2 = pinTCC1 | 2 pinTCC1_4 = pinTCC1 | 4 pinTCC1_6 = pinTCC1 | 6 pinTCC2_0 = pinTCC2 | 0 pinTCC2_2 = pinTCC2 | 2 pinTCC3_0 = pinTCC3 | 0 pinTCC4_0 = pinTCC4 | 0 ) // This is a copy of columns F and G (the TCC columns) of table 6-1 in the // datasheet: // http://ww1.microchip.com/downloads/en/DeviceDoc/60001507E.pdf // For example, "TCC0/WO[2]" is converted to pinTCC0_2. // Only the even pin numbers are stored here. The odd pin numbers are left out, // because their PWM output can be determined from the even number: just add one // to the wave output (WO) number. var pinTimerMapping = [...]struct{ F, G uint8 }{ // page 33 PC04 / 2: {pinTCC0_0, 0}, PA08 / 2: {pinTCC0_0, pinTCC1_4}, PA10 / 2: {pinTCC0_2, pinTCC1_6}, PB10 / 2: {pinTCC0_4, pinTCC1_0}, PB12 / 2: {pinTCC3_0, pinTCC0_0}, PB14 / 2: {pinTCC4_0, pinTCC0_2}, PD08 / 2: {pinTCC0_1, 0}, PD10 / 2: {pinTCC0_3, 0}, PD12 / 2: {pinTCC0_5, 0}, PC10 / 2: {pinTCC0_0, pinTCC1_4}, // page 34 PC12 / 2: {pinTCC0_2, pinTCC1_6}, PC14 / 2: {pinTCC0_4, pinTCC1_0}, PA12 / 2: {pinTCC0_6, pinTCC1_2}, PA14 / 2: {pinTCC2_0, pinTCC1_2}, PA16 / 2: {pinTCC1_0, pinTCC0_4}, PA18 / 2: {pinTCC1_2, pinTCC0_6}, PC16 / 2: {pinTCC0_0, 0}, PC18 / 2: {pinTCC0_2, 0}, PC20 / 2: {pinTCC0_4, 0}, PC22 / 2: {pinTCC0_6, 0}, PD20 / 2: {pinTCC1_0, 0}, PB16 / 2: {pinTCC3_0, pinTCC0_4}, PB18 / 2: {pinTCC1_0, 0}, // page 35 PB20 / 2: {pinTCC1_2, 0}, PA20 / 2: {pinTCC1_4, pinTCC0_0}, PA22 / 2: {pinTCC1_6, pinTCC0_2}, PA24 / 2: {pinTCC2_2, 0}, PB26 / 2: {pinTCC1_2, 0}, PB28 / 2: {pinTCC1_4, 0}, PA30 / 2: {pinTCC2_0, 0}, // page 36 PB30 / 2: {pinTCC4_0, pinTCC0_6}, PB02 / 2: {pinTCC2_2, 0}, } // findPinPadMapping returns the pin mode (PinTCCF or PinTCCG) and the channel // number for a given timer and pin. A zero PinMode is returned if no mapping // could be found. func findPinTimerMapping(timer uint8, pin Pin) (PinMode, uint8) { if int(pin/2) >= len(pinTimerMapping) { return 0, 0 // invalid pin number } mapping := pinTimerMapping[pin/2] // Check for column F in the datasheet. if mapping.F>>4-1 == timer { return PinTCCF, mapping.F&0x0f + uint8(pin)&1 } // Check for column G in the datasheet. if mapping.G>>4-1 == timer { return PinTCCG, mapping.G&0x0f + uint8(pin)&1 } // Nothing found. return 0, 0 } // Channel returns a PWM channel for the given pin. Note that one channel may be // shared between multiple pins, and so will have the same duty cycle. If this // is not desirable, look for a different TCC or consider using a different pin. func (tcc *TCC) Channel(pin Pin) (uint8, error) { pinMode, woOutput := findPinTimerMapping(tcc.timerNum(), pin) if pinMode == 0 { // No pin could be found. return 0, ErrInvalidOutputPin } // Convert from waveform output to channel, assuming WEXCTRL.OTMX equals 0. // See table 49-4 "Output Matrix Channel Pin Routing Configuration" on page // 1829 of the datasheet. // The number of channels varies by TCC instance, hence the need to switch // over them. For TCC2-4 the number of channels is equal to the number of // waveform outputs, so the WO number maps directly to the channel number. // For TCC0 and TCC1 this is not the case so they will need some special // handling. channel := woOutput switch tcc.timer() { case sam.TCC0: channel = woOutput % 6 case sam.TCC1: channel = woOutput % 4 } // Enable the port multiplexer for pin pin.setPinCfg(sam.PORT_GROUP_PINCFG_PMUXEN) // Connect timer/mux to pin. if pin&1 > 0 { // odd pin, so save the even pins val := pin.getPMux() & sam.PORT_GROUP_PMUX_PMUXE_Msk pin.setPMux(val | uint8(pinMode<> 4) dac.syncDAC() return nil } func (dac DAC) syncDAC() { switch dac.Channel { case 0: for !sam.DAC.STATUS.HasBits(sam.DAC_STATUS_EOC0) { } for sam.DAC.SYNCBUSY.HasBits(sam.DAC_SYNCBUSY_DATA0) { } default: for !sam.DAC.STATUS.HasBits(sam.DAC_STATUS_EOC1) { } for sam.DAC.SYNCBUSY.HasBits(sam.DAC_SYNCBUSY_DATA1) { } } } // GetRNG returns 32 bits of cryptographically secure random data func GetRNG() (uint32, error) { if !sam.MCLK.APBCMASK.HasBits(sam.MCLK_APBCMASK_TRNG_) { // Turn on clock for TRNG sam.MCLK.APBCMASK.SetBits(sam.MCLK_APBCMASK_TRNG_) // enable sam.TRNG.CTRLA.Set(sam.TRNG_CTRLA_ENABLE) } for !sam.TRNG.INTFLAG.HasBits(sam.TRNG_INTFLAG_DATARDY) { } ret := sam.TRNG.DATA.Get() return ret, nil } // Flash related code const memoryStart = 0x0 // compile-time check for ensuring we fulfill BlockDevice interface var _ BlockDevice = flashBlockDevice{} var Flash flashBlockDevice type flashBlockDevice struct { initComplete bool } // ReadAt reads the given number of bytes from the block device. func (f flashBlockDevice) ReadAt(p []byte, off int64) (n int, err error) { if FlashDataStart()+uintptr(off)+uintptr(len(p)) > FlashDataEnd() { return 0, errFlashCannotReadPastEOF } waitWhileFlashBusy() data := unsafe.Slice((*byte)(unsafe.Add(unsafe.Pointer(FlashDataStart()), uintptr(off))), len(p)) copy(p, data) return len(p), nil } // WriteAt writes the given number of bytes to the block device. // Only word (32 bits) length data can be programmed. // See SAM-D5x-E5x-Family-Data-Sheet-DS60001507.pdf page 591-592. // If the length of p is not long enough it will be padded with 0xFF bytes. // This method assumes that the destination is already erased. func (f flashBlockDevice) WriteAt(p []byte, off int64) (n int, err error) { if FlashDataStart()+uintptr(off)+uintptr(len(p)) > FlashDataEnd() { return 0, errFlashCannotWritePastEOF } address := FlashDataStart() + uintptr(off) padded := f.pad(p) settings := disableFlashCache() defer restoreFlashCache(settings) waitWhileFlashBusy() sam.NVMCTRL.CTRLB.Set(sam.NVMCTRL_CTRLB_CMD_PBC | (sam.NVMCTRL_CTRLB_CMDEX_KEY << sam.NVMCTRL_CTRLB_CMDEX_Pos)) waitWhileFlashBusy() for j := 0; j < len(padded); j += int(f.WriteBlockSize()) { // write first word using double-word low order word *(*uint32)(unsafe.Pointer(address)) = binary.LittleEndian.Uint32(padded[j : j+int(f.WriteBlockSize()/2)]) // write second word using double-word high order word *(*uint32)(unsafe.Add(unsafe.Pointer(address), uintptr(f.WriteBlockSize())/2)) = binary.LittleEndian.Uint32(padded[j+int(f.WriteBlockSize()/2) : j+int(f.WriteBlockSize())]) waitWhileFlashBusy() sam.NVMCTRL.SetADDR(uint32(address)) sam.NVMCTRL.CTRLB.Set(sam.NVMCTRL_CTRLB_CMD_WQW | (sam.NVMCTRL_CTRLB_CMDEX_KEY << sam.NVMCTRL_CTRLB_CMDEX_Pos)) waitWhileFlashBusy() if err := checkFlashError(); err != nil { return j, err } address += uintptr(f.WriteBlockSize()) } return len(padded), nil } // Size returns the number of bytes in this block device. func (f flashBlockDevice) Size() int64 { return int64(FlashDataEnd() - FlashDataStart()) } const writeBlockSize = 8 // WriteBlockSize returns the block size in which data can be written to // memory. It can be used by a client to optimize writes, non-aligned writes // should always work correctly. func (f flashBlockDevice) WriteBlockSize() int64 { return writeBlockSize } const eraseBlockSizeValue = 8192 func eraseBlockSize() int64 { return eraseBlockSizeValue } // EraseBlockSize returns the smallest erasable area on this particular chip // in bytes. This is used for the block size in EraseBlocks. func (f flashBlockDevice) EraseBlockSize() int64 { return eraseBlockSize() } // EraseBlocks erases the given number of blocks. An implementation may // transparently coalesce ranges of blocks into larger bundles if the chip // supports this. The start and len parameters are in block numbers, use // EraseBlockSize to map addresses to blocks. func (f flashBlockDevice) EraseBlocks(start, len int64) error { address := FlashDataStart() + uintptr(start*f.EraseBlockSize()) settings := disableFlashCache() defer restoreFlashCache(settings) waitWhileFlashBusy() for i := start; i < start+len; i++ { sam.NVMCTRL.SetADDR(uint32(address)) sam.NVMCTRL.CTRLB.Set(sam.NVMCTRL_CTRLB_CMD_EB | (sam.NVMCTRL_CTRLB_CMDEX_KEY << sam.NVMCTRL_CTRLB_CMDEX_Pos)) waitWhileFlashBusy() if err := checkFlashError(); err != nil { return err } address += uintptr(f.EraseBlockSize()) } return nil } // pad data if needed so it is long enough for correct byte alignment on writes. func (f flashBlockDevice) pad(p []byte) []byte { overflow := int64(len(p)) % f.WriteBlockSize() if overflow == 0 { return p } padding := bytes.Repeat([]byte{0xff}, int(f.WriteBlockSize()-overflow)) return append(p, padding...) } func disableFlashCache() uint16 { settings := sam.NVMCTRL.CTRLA.Get() // disable caches sam.NVMCTRL.SetCTRLA_CACHEDIS0(1) sam.NVMCTRL.SetCTRLA_CACHEDIS1(1) waitWhileFlashBusy() return settings } func restoreFlashCache(settings uint16) { sam.NVMCTRL.CTRLA.Set(settings) waitWhileFlashBusy() } func waitWhileFlashBusy() { for sam.NVMCTRL.GetSTATUS_READY() != sam.NVMCTRL_STATUS_READY { } } var ( errFlashADDRE = errors.New("errFlashADDRE") errFlashPROGE = errors.New("errFlashPROGE") errFlashLOCKE = errors.New("errFlashLOCKE") errFlashECCSE = errors.New("errFlashECCSE") errFlashNVME = errors.New("errFlashNVME") errFlashSEESOVF = errors.New("errFlashSEESOVF") ) func checkFlashError() error { switch { case sam.NVMCTRL.GetINTENSET_ADDRE() != 0: return errFlashADDRE case sam.NVMCTRL.GetINTENSET_PROGE() != 0: return errFlashPROGE case sam.NVMCTRL.GetINTENSET_LOCKE() != 0: return errFlashLOCKE case sam.NVMCTRL.GetINTENSET_ECCSE() != 0: return errFlashECCSE case sam.NVMCTRL.GetINTENSET_NVME() != 0: return errFlashNVME case sam.NVMCTRL.GetINTENSET_SEESOVF() != 0: return errFlashSEESOVF } return nil }