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// +build nrf52840
package machine
import (
"device/nrf"
"unsafe"
)
const CPU_FREQUENCY = 64000000
// Get peripheral and pin number for this GPIO pin.
func (p GPIO) getPortPin() (*nrf.GPIO_Type, uint8) {
if p.Pin >= 32 {
return nrf.P1, p.Pin - 32
} else {
return nrf.P0, p.Pin
}
}
func (uart UART) setPins(tx, rx uint32) {
nrf.UART0.PSEL.TXD = nrf.RegValue(tx)
nrf.UART0.PSEL.RXD = nrf.RegValue(rx)
}
//go:export UARTE0_UART0_IRQHandler
func handleUART0() {
UART0.handleInterrupt()
}
func (i2c I2C) setPins(scl, sda uint8) {
i2c.Bus.PSEL.SCL = nrf.RegValue(scl)
i2c.Bus.PSEL.SDA = nrf.RegValue(sda)
}
// SPI
func (spi SPI) setPins(sck, mosi, miso uint8) {
if sck == 0 {
sck = SPI0_SCK_PIN
}
if mosi == 0 {
mosi = SPI0_MOSI_PIN
}
if miso == 0 {
miso = SPI0_MISO_PIN
}
spi.Bus.PSEL.SCK = nrf.RegValue(sck)
spi.Bus.PSEL.MOSI = nrf.RegValue(mosi)
spi.Bus.PSEL.MISO = nrf.RegValue(miso)
}
// InitADC initializes the registers needed for ADC.
func InitADC() {
return // no specific setup on nrf52840 machine.
}
// Configure configures an ADC pin to be able to read analog data.
func (a ADC) Configure() {
return // no pin specific setup on nrf52840 machine.
}
// Get returns the current value of a ADC pin in the range 0..0xffff.
func (a ADC) Get() uint16 {
var pwmPin uint32
var value int16
switch a.Pin {
case 2:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput0
case 3:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput1
case 4:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput2
case 5:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput3
case 28:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput4
case 29:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput5
case 30:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput6
case 31:
pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput7
default:
return 0
}
nrf.SAADC.RESOLUTION = nrf.SAADC_RESOLUTION_VAL_12bit
// Enable ADC.
nrf.SAADC.ENABLE = (nrf.SAADC_ENABLE_ENABLE_Enabled << nrf.SAADC_ENABLE_ENABLE_Pos)
for i := 0; i < 8; i++ {
nrf.SAADC.CH[i].PSELN = nrf.SAADC_CH_PSELP_PSELP_NC
nrf.SAADC.CH[i].PSELP = nrf.SAADC_CH_PSELP_PSELP_NC
}
// Configure ADC.
nrf.SAADC.CH[0].CONFIG = ((nrf.SAADC_CH_CONFIG_RESP_Bypass << nrf.SAADC_CH_CONFIG_RESP_Pos) & nrf.SAADC_CH_CONFIG_RESP_Msk) |
((nrf.SAADC_CH_CONFIG_RESP_Bypass << nrf.SAADC_CH_CONFIG_RESN_Pos) & nrf.SAADC_CH_CONFIG_RESN_Msk) |
((nrf.SAADC_CH_CONFIG_GAIN_Gain1_5 << nrf.SAADC_CH_CONFIG_GAIN_Pos) & nrf.SAADC_CH_CONFIG_GAIN_Msk) |
((nrf.SAADC_CH_CONFIG_REFSEL_Internal << nrf.SAADC_CH_CONFIG_REFSEL_Pos) & nrf.SAADC_CH_CONFIG_REFSEL_Msk) |
((nrf.SAADC_CH_CONFIG_TACQ_3us << nrf.SAADC_CH_CONFIG_TACQ_Pos) & nrf.SAADC_CH_CONFIG_TACQ_Msk) |
((nrf.SAADC_CH_CONFIG_MODE_SE << nrf.SAADC_CH_CONFIG_MODE_Pos) & nrf.SAADC_CH_CONFIG_MODE_Msk)
// Set pin to read.
nrf.SAADC.CH[0].PSELN = nrf.RegValue(pwmPin)
nrf.SAADC.CH[0].PSELP = nrf.RegValue(pwmPin)
// Destination for sample result.
nrf.SAADC.RESULT.PTR = nrf.RegValue(uintptr(unsafe.Pointer(&value)))
nrf.SAADC.RESULT.MAXCNT = 1 // One sample
// Start tasks.
nrf.SAADC.TASKS_START = 1
for nrf.SAADC.EVENTS_STARTED == 0 {
}
nrf.SAADC.EVENTS_STARTED = 0x00
// Start the sample task.
nrf.SAADC.TASKS_SAMPLE = 1
// Wait until the sample task is done.
for nrf.SAADC.EVENTS_END == 0 {
}
nrf.SAADC.EVENTS_END = 0x00
// Stop the ADC
nrf.SAADC.TASKS_STOP = 1
for nrf.SAADC.EVENTS_STOPPED == 0 {
}
nrf.SAADC.EVENTS_STOPPED = 0
// Disable the ADC.
nrf.SAADC.ENABLE = (nrf.SAADC_ENABLE_ENABLE_Disabled << nrf.SAADC_ENABLE_ENABLE_Pos)
if value < 0 {
value = 0
}
// Return 16-bit result from 12-bit value.
return uint16(value << 4)
}
// PWM
var (
pwmChannelPins = [4]uint32{0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}
pwms = [4]*nrf.PWM_Type{nrf.PWM0, nrf.PWM1, nrf.PWM2, nrf.PWM3}
pwmChannelSequence [4]uint16
)
// InitPWM initializes the registers needed for PWM.
func InitPWM() {
return
}
// Configure configures a PWM pin for output.
func (pwm PWM) Configure() {
}
// Set turns on the duty cycle for a PWM pin using the provided value.
func (pwm PWM) Set(value uint16) {
for i := 0; i < 4; i++ {
if pwmChannelPins[i] == 0xFFFFFFFF || pwmChannelPins[i] == uint32(pwm.Pin) {
pwmChannelPins[i] = uint32(pwm.Pin)
pwmChannelSequence[i] = (value >> 2) | 0x8000 // set bit 15 to invert polarity
p := pwms[i]
p.PSEL.OUT[0] = nrf.RegValue(pwm.Pin)
p.PSEL.OUT[1] = nrf.RegValue(pwm.Pin)
p.PSEL.OUT[2] = nrf.RegValue(pwm.Pin)
p.PSEL.OUT[3] = nrf.RegValue(pwm.Pin)
p.ENABLE = (nrf.PWM_ENABLE_ENABLE_Enabled << nrf.PWM_ENABLE_ENABLE_Pos)
p.PRESCALER = nrf.PWM_PRESCALER_PRESCALER_DIV_2
p.MODE = nrf.PWM_MODE_UPDOWN_Up
p.COUNTERTOP = 16384 // frequency
p.LOOP = 0
p.DECODER = (nrf.PWM_DECODER_LOAD_Common << nrf.PWM_DECODER_LOAD_Pos) | (nrf.PWM_DECODER_MODE_RefreshCount << nrf.PWM_DECODER_MODE_Pos)
p.SEQ[0].PTR = nrf.RegValue(uintptr(unsafe.Pointer(&pwmChannelSequence[i])))
p.SEQ[0].CNT = 1
p.SEQ[0].REFRESH = 1
p.SEQ[0].ENDDELAY = 0
p.TASKS_SEQSTART[0] = 1
break
}
}
}
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