avr: unify GPIO pin/port code
All the AVRs that I've looked at had the same pin/port structure, with the possible states being input/floating, input/pullup, low, and high (with the same PORT/DDR registers). The main difference is the number of available ports and pins. To reduce the amount of code and avoid duplication (and thus errors) I decided to centralize this, following the design used by the atmega2560 but while using a trick to save tracking a few registers. In the process, I noticed that the Pin.Get() function was incorrect on the atmega2560 implementation. It is now fixed in the unified code.
Этот коммит содержится в:
Ayke van Laethem
Ron Evans
родитель
424d775bf4
коммит
da505a6b17
5 изменённых файлов: 111 добавлений и 99 удалений
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@ -14,12 +14,58 @@ func CPUFrequency() uint32 {
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return 20000000
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}
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const (
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portA Pin = iota * 8
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portB
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portC
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portD
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)
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const (
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PA0 = portA + 0
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PA1 = portA + 1
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PA2 = portA + 2
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PA3 = portA + 3
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PA4 = portA + 4
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PA5 = portA + 5
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PA6 = portA + 6
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PA7 = portA + 7
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PB0 = portB + 0
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PB1 = portB + 1
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PB2 = portB + 2
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PB3 = portB + 3
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PB4 = portB + 4
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PB5 = portB + 5
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PB6 = portB + 6
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PB7 = portB + 7
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PC0 = portC + 0
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PC1 = portC + 1
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PC2 = portC + 2
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PC3 = portC + 3
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PC4 = portC + 4
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PC5 = portC + 5
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PC6 = portC + 6
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PC7 = portC + 7
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PD0 = portD + 0
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PD1 = portD + 1
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PD2 = portD + 2
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PD3 = portD + 3
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PD4 = portD + 4
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PD5 = portD + 5
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PD6 = portD + 6
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PD7 = portD + 7
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)
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// getPortMask returns the PORTx register and mask for the pin.
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func (p Pin) getPortMask() (*volatile.Register8, uint8) {
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if p < 8 {
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return avr.PORTD, 1 << uint8(p)
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} else if p < 14 {
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return avr.PORTB, 1 << uint8(p-8)
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} else {
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return avr.PORTC, 1 << uint8(p-14)
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switch {
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case p >= PA0 && p <= PA7:
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return avr.PORTA, 1 << uint8(p-portA)
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case p >= PB0 && p <= PB7:
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return avr.PORTB, 1 << uint8(p-portB)
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case p >= PC0 && p <= PC7:
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return avr.PORTC, 1 << uint8(p-portC)
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default:
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return avr.PORTD, 1 << uint8(p-portD)
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}
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}
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@ -96,53 +96,32 @@ const (
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PL7 = portE + 7
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)
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// Configure sets the pin to input or output.
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func (p Pin) Configure(config PinConfig) {
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register, _, mask := p.getRegisterPortMask()
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if config.Mode == PinOutput { // set output bit
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register.SetBits(mask)
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} else { // configure input: clear output bit
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register.ClearBits(mask)
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}
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}
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// Get returns the current value of a GPIO pin.
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func (p Pin) Get() bool {
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_, port, mask := p.getRegisterPortMask()
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return (port.Get() & mask) > 0
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}
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// getPortMask returns the PORTx register and mask for the pin.
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func (p Pin) getPortMask() (*volatile.Register8, uint8) {
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_, port, mask := p.getRegisterPortMask()
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return port, mask
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}
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// getRegisterPortMask returns the register, port, and mask for the pin
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func (p Pin) getRegisterPortMask() (*volatile.Register8, *volatile.Register8, uint8) {
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switch {
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case p >= PA0 && p <= PA7:
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return avr.DDRA, avr.PORTA, 1 << uint8(p-portA)
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return avr.PORTA, 1 << uint8(p-portA)
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case p >= PB0 && p <= PB7:
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return avr.DDRB, avr.PORTB, 1 << uint8(p-portB)
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return avr.PORTB, 1 << uint8(p-portB)
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case p >= PC0 && p <= PC7:
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return avr.DDRC, avr.PORTC, 1 << uint8(p-portC)
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return avr.PORTC, 1 << uint8(p-portC)
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case p >= PD0 && p <= PD7:
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return avr.DDRD, avr.PORTD, 1 << uint8(p-portD)
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return avr.PORTD, 1 << uint8(p-portD)
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case p >= PE0 && p <= PE6:
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return avr.DDRE, avr.PORTE, 1 << uint8(p-portE)
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return avr.PORTE, 1 << uint8(p-portE)
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case p >= PF0 && p <= PF7:
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return avr.DDRF, avr.PORTF, 1 << uint8(p-portF)
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return avr.PORTF, 1 << uint8(p-portF)
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case p >= PG0 && p <= PG5:
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return avr.DDRG, avr.PORTG, 1 << uint8(p-portG)
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return avr.PORTG, 1 << uint8(p-portG)
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case p >= PH0 && p <= PH6:
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return avr.DDRH, avr.PORTH, 1 << uint8(p-portH)
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return avr.PORTH, 1 << uint8(p-portH)
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case p >= PJ0 && p <= PJ1:
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return avr.DDRJ, avr.PORTJ, 1 << uint8(p-portJ)
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return avr.PORTJ, 1 << uint8(p-portJ)
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case p >= PK0 && p <= PK7:
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return avr.DDRK, avr.PORTK, 1 << uint8(p-portK)
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return avr.PORTK, 1 << uint8(p-portK)
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case p >= PL0 && p <= PL7:
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return avr.DDRL, avr.PORTL, 1 << uint8(p-portL)
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return avr.PORTL, 1 << uint8(p-portL)
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default:
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return avr.DDRB, avr.PORTA, 255
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return avr.PORTA, 255
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}
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}
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@ -9,51 +9,15 @@ import (
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const irq_USART0_RX = avr.IRQ_USART_RX
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// Configure sets the pin to input or output.
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func (p Pin) Configure(config PinConfig) {
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if config.Mode == PinOutput { // set output bit
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switch p / 8 {
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case 0: // port B
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avr.DDRB.SetBits(1 << uint8(p))
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case 1: // port C
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avr.DDRC.SetBits(1 << uint8(p-8))
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case 2: // port D
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avr.DDRD.SetBits(1 << uint8(p-16))
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}
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} else { // configure input: clear output bit
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switch p / 8 {
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case 0: // port B
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avr.DDRB.ClearBits(1 << uint8(p))
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case 1: // port C
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avr.DDRC.ClearBits(1 << uint8(p-8))
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case 2: // port D
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avr.DDRD.ClearBits(1 << uint8(p-16))
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}
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}
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}
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// Get returns the current value of a GPIO pin.
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func (p Pin) Get() bool {
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var val uint8
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switch p / 8 {
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case 0: // port B
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val = avr.PINB.Get() & (1 << uint8(p))
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case 1: // port C
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val = avr.PINC.Get() & (1 << uint8(p-8))
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case 2: // port D
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val = avr.PIND.Get() & (1 << uint8(p-16))
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}
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return val != 0
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}
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// getPortMask returns the PORTx register and mask for the pin.
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func (p Pin) getPortMask() (*volatile.Register8, uint8) {
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switch p / 8 {
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case 0: // port B
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return avr.PORTB, 1 << uint8(p)
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case 1:
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return avr.PORTC, 1 << uint8(p-8)
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default:
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return avr.PORTD, 1 << uint8(p-16)
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switch {
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case p >= PB0 && p <= PB7: // port B
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return avr.PORTB, 1 << uint8(p-portB)
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case p >= PC0 && p <= PC7: // port C
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return avr.PORTC, 1 << uint8(p-portC)
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default: // port D
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return avr.PORTD, 1 << uint8(p-portD)
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}
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}
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@ -16,21 +16,8 @@ const (
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PB5
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)
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// Configure sets the pin to input or output.
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func (p Pin) Configure(config PinConfig) {
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if config.Mode == PinOutput { // set output bit
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avr.DDRB.SetBits(1 << uint8(p))
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} else { // configure input: clear output bit
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avr.DDRB.ClearBits(1 << uint8(p))
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}
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}
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// getPortMask returns the PORTx register and mask for the pin.
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func (p Pin) getPortMask() (*volatile.Register8, uint8) {
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// Very simple for the attiny85, which only has a single port.
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return avr.PORTB, 1 << uint8(p)
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}
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// Get returns the current value of a GPIO pin.
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func (p Pin) Get() bool {
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val := avr.PINB.Get() & (1 << uint8(p))
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return (val > 0)
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}
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@ -5,6 +5,7 @@ package machine
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import (
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"device/avr"
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"runtime/volatile"
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"unsafe"
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)
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type PinMode uint8
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@ -14,6 +15,41 @@ const (
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PinOutput
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)
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// In all the AVRs I've looked at, the PIN/DDR/PORT registers followed a regular
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// pattern: PINx, DDRx, PORTx in this order without registers in between.
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// Therefore, if you know any of them, you can calculate the other two.
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//
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// For now, I've chosen to let the PORTx register be the one that is returned
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// for each specific chip and to calculate the others from that one. Setting an
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// output port (done using PORTx) is likely the most common operation and the
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// one that is the most time critical. For others, the PINx and DDRx register
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// can trivially be calculated using a subtraction.
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// Configure sets the pin to input or output.
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func (p Pin) Configure(config PinConfig) {
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port, mask := p.getPortMask()
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// The DDRx register can be found by subtracting one from the PORTx
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// register, as this appears to be the case for many (most? all?) AVR chips.
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ddr := (*volatile.Register8)(unsafe.Pointer(uintptr(unsafe.Pointer(port)) - 1))
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if config.Mode == PinOutput {
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// set output bit
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ddr.SetBits(mask)
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} else {
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// configure input: clear output bit
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ddr.ClearBits(mask)
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}
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}
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// Get returns the current value of a GPIO pin.
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func (p Pin) Get() bool {
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port, mask := p.getPortMask()
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// As noted above, the PINx register is always two registers below the PORTx
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// register, so we can find it simply by subtracting two from the PORTx
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// register address.
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pin := (*volatile.Register8)(unsafe.Pointer(uintptr(unsafe.Pointer(port)) - 2)) // PINA, PINB, etc
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return (pin.Get() & mask) > 0
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}
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// Set changes the value of the GPIO pin. The pin must be configured as output.
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func (p Pin) Set(value bool) {
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if value { // set bits
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