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//go:build avr && atmega328pb
package machine
import (
"device/avr"
"runtime/volatile"
)
const irq_USART0_RX = avr.IRQ_USART0_RX
// getPortMask returns the PORTx register and mask for the pin.
func (p Pin) getPortMask() (*volatile.Register8, uint8) {
switch {
case p >= PB0 && p <= PB7: // port B
return avr.PORTB, 1 << uint8(p-portB)
case p >= PC0 && p <= PC7: // port C
return avr.PORTC, 1 << uint8(p-portC)
default: // port D
return avr.PORTD, 1 << uint8(p-portD)
}
}
// InitPWM initializes the registers needed for PWM.
func InitPWM() {
// use waveform generation
avr.TCCR0A.SetBits(avr.TCCR0A_WGM00)
// set timer 0 prescale factor to 64
avr.TCCR0B.SetBits(avr.TCCR0B_CS01 | avr.TCCR0B_CS00)
// set timer 1 prescale factor to 64
avr.TCCR1B.SetBits(avr.TCCR1B_CS11)
// put timer 1 in 8-bit phase correct pwm mode
avr.TCCR1A.SetBits(avr.TCCR1A_WGM10)
// set timer 2 prescale factor to 64
avr.TCCR2B.SetBits(avr.TCCR2B_CS22)
// configure timer 2 for phase correct pwm (8-bit)
avr.TCCR2A.SetBits(avr.TCCR2A_WGM20)
}
// Configure configures a PWM pin for output.
func (pwm PWM) Configure() error {
switch pwm.Pin / 8 {
case 0: // port B
avr.DDRB.SetBits(1 << uint8(pwm.Pin))
case 2: // port D
avr.DDRD.SetBits(1 << uint8(pwm.Pin-16))
}
return nil
}
// Set turns on the duty cycle for a PWM pin using the provided value. On the AVR this is normally a
// 8-bit value ranging from 0 to 255.
func (pwm PWM) Set(value uint16) {
value8 := uint8(value >> 8)
switch pwm.Pin {
case PD3:
// connect pwm to pin on timer 2, channel B
avr.TCCR2A.SetBits(avr.TCCR2A_COM2B1)
avr.OCR2B.Set(value8) // set pwm duty
case PD5:
// connect pwm to pin on timer 0, channel B
avr.TCCR0A.SetBits(avr.TCCR0A_COM0B1)
avr.OCR0B.Set(value8) // set pwm duty
case PD6:
// connect pwm to pin on timer 0, channel A
avr.TCCR0A.SetBits(avr.TCCR0A_COM0A1)
avr.OCR0A.Set(value8) // set pwm duty
case PB1:
// connect pwm to pin on timer 1, channel A
avr.TCCR1A.SetBits(avr.TCCR1A_COM1A1)
// this is a 16-bit value, but we only currently allow the low order bits to be set
avr.OCR1AL.Set(value8) // set pwm duty
case PB2:
// connect pwm to pin on timer 1, channel B
avr.TCCR1A.SetBits(avr.TCCR1A_COM1B1)
// this is a 16-bit value, but we only currently allow the low order bits to be set
avr.OCR1BL.Set(value8) // set pwm duty
case PB3:
// connect pwm to pin on timer 2, channel A
avr.TCCR2A.SetBits(avr.TCCR2A_COM2A1)
avr.OCR2A.Set(value8) // set pwm duty
default:
panic("Invalid PWM pin")
}
}
// SPI configuration
var SPI0 = SPI{
spcr: avr.SPCR0,
spdr: avr.SPDR0,
spsr: avr.SPSR0,
sck: PB5,
sdo: PB3,
sdi: PB4,
cs: PB2}
var SPI1 = SPI{
spcr: avr.SPCR1,
spdr: avr.SPDR1,
spsr: avr.SPSR1,
sck: PC1,
sdo: PE3,
sdi: PC0,
cs: PE2}
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