mirror of
https://github.com/tinygo-org/tinygo.git
synced 2026-08-06 20:13:40 +00:00
Ron Evans
646 lines
16 KiB
Go
646 lines
16 KiB
Go
// +build sam,atsamd21g18a
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// Peripheral abstraction layer for the atsamd21.
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//
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// Datasheet:
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// http://ww1.microchip.com/downloads/en/DeviceDoc/SAMD21-Family-DataSheet-DS40001882D.pdf
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//
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package machine
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import (
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"device/arm"
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"device/sam"
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"errors"
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)
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const CPU_FREQUENCY = 48000000
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type GPIOMode uint8
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const (
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GPIO_ANALOG = 1
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GPIO_SERCOM = 2
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GPIO_SERCOM_ALT = 3
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GPIO_TIMER = 4
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GPIO_TIMER_ALT = 5
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GPIO_COM = 6
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GPIO_AC_CLK = 7
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GPIO_DIGITAL = 8
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GPIO_INPUT = 9
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GPIO_INPUT_PULLUP = 10
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GPIO_OUTPUT = 11
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GPIO_PWM = GPIO_TIMER
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GPIO_PWM_ALT = GPIO_TIMER_ALT
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)
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// Configure this pin with the given configuration.
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func (p GPIO) Configure(config GPIOConfig) {
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switch config.Mode {
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case GPIO_OUTPUT:
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sam.PORT.DIRSET0 = (1 << p.Pin)
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// output is also set to input enable so pin can read back its own value
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p.setPinCfg(sam.PORT_PINCFG0_INEN)
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case GPIO_INPUT:
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sam.PORT.DIRCLR0 = (1 << p.Pin)
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p.setPinCfg(sam.PORT_PINCFG0_INEN)
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case GPIO_SERCOM:
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if p.Pin&1 > 0 {
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// odd pin, so save the even pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXE_Msk
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p.setPMux(val | (GPIO_SERCOM << sam.PORT_PMUX0_PMUXO_Pos))
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} else {
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// even pin, so save the odd pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXO_Msk
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p.setPMux(val | (GPIO_SERCOM << sam.PORT_PMUX0_PMUXE_Pos))
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}
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// enable port config
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p.setPinCfg(sam.PORT_PINCFG0_PMUXEN | sam.PORT_PINCFG0_DRVSTR | sam.PORT_PINCFG0_INEN)
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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 GPIO) Get() bool {
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return (sam.PORT.IN0>>p.Pin)&1 > 0
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}
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// Set the pin to high or low.
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// Warning: only use this on an output pin!
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func (p GPIO) Set(high bool) {
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if high {
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sam.PORT.OUTSET0 = (1 << p.Pin)
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} else {
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sam.PORT.OUTCLR0 = (1 << p.Pin)
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}
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}
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// getPMux returns the value for the correct PMUX register for this pin.
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func (p GPIO) getPMux() sam.RegValue8 {
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pin := p.Pin >> 1
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switch pin {
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case 0:
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return sam.PORT.PMUX0_0
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case 1:
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return sam.PORT.PMUX0_1
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case 2:
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return sam.PORT.PMUX0_2
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case 3:
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return sam.PORT.PMUX0_3
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case 4:
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return sam.PORT.PMUX0_4
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case 5:
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return sam.PORT.PMUX0_5
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case 6:
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return sam.PORT.PMUX0_6
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case 7:
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return sam.PORT.PMUX0_7
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case 8:
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return sam.PORT.PMUX0_8
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case 9:
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return sam.PORT.PMUX0_9
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case 10:
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return sam.PORT.PMUX0_10
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case 11:
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return sam.PORT.PMUX0_11
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case 12:
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return sam.PORT.PMUX0_12
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case 13:
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return sam.PORT.PMUX0_13
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case 14:
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return sam.PORT.PMUX0_14
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case 15:
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return sam.PORT.PMUX0_15
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default:
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return 0
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}
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}
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// setPMux sets the value for the correct PMUX register for this pin.
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func (p GPIO) setPMux(val sam.RegValue8) {
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pin := p.Pin >> 1
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switch pin {
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case 0:
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sam.PORT.PMUX0_0 = val
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case 1:
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sam.PORT.PMUX0_1 = val
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case 2:
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sam.PORT.PMUX0_2 = val
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case 3:
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sam.PORT.PMUX0_3 = val
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case 4:
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sam.PORT.PMUX0_4 = val
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case 5:
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sam.PORT.PMUX0_5 = val
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case 6:
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sam.PORT.PMUX0_6 = val
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case 7:
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sam.PORT.PMUX0_7 = val
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case 8:
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sam.PORT.PMUX0_8 = val
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case 9:
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sam.PORT.PMUX0_9 = val
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case 10:
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sam.PORT.PMUX0_10 = val
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case 11:
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sam.PORT.PMUX0_11 = val
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case 12:
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sam.PORT.PMUX0_12 = val
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case 13:
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sam.PORT.PMUX0_13 = val
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case 14:
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sam.PORT.PMUX0_14 = val
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case 15:
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sam.PORT.PMUX0_15 = val
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}
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}
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// getPinCfg returns the value for the correct PINCFG register for this pin.
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func (p GPIO) getPinCfg() sam.RegValue8 {
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switch p.Pin {
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case 0:
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return sam.PORT.PINCFG0_0
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case 1:
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return sam.PORT.PINCFG0_1
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case 2:
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return sam.PORT.PINCFG0_2
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case 3:
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return sam.PORT.PINCFG0_3
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case 4:
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return sam.PORT.PINCFG0_4
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case 5:
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return sam.PORT.PINCFG0_5
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case 6:
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return sam.PORT.PINCFG0_6
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case 7:
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return sam.PORT.PINCFG0_7
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case 8:
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return sam.PORT.PINCFG0_8
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case 9:
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return sam.PORT.PINCFG0_9
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case 10:
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return sam.PORT.PINCFG0_10
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case 11:
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return sam.PORT.PINCFG0_11
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case 12:
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return sam.PORT.PINCFG0_12
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case 13:
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return sam.PORT.PINCFG0_13
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case 14:
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return sam.PORT.PINCFG0_14
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case 15:
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return sam.PORT.PINCFG0_15
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case 16:
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return sam.PORT.PINCFG0_16
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case 17:
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return sam.PORT.PINCFG0_17
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case 18:
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return sam.PORT.PINCFG0_18
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case 19:
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return sam.PORT.PINCFG0_19
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case 20:
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return sam.PORT.PINCFG0_20
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case 21:
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return sam.PORT.PINCFG0_21
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case 22:
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return sam.PORT.PINCFG0_22
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case 23:
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return sam.PORT.PINCFG0_23
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case 24:
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return sam.PORT.PINCFG0_24
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case 25:
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return sam.PORT.PINCFG0_25
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case 26:
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return sam.PORT.PINCFG0_26
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case 27:
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return sam.PORT.PINCFG0_27
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case 28:
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return sam.PORT.PINCFG0_28
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case 29:
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return sam.PORT.PINCFG0_29
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case 30:
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return sam.PORT.PINCFG0_30
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case 31:
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return sam.PORT.PINCFG0_31
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default:
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return 0
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}
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}
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// setPinCfg sets the value for the correct PINCFG register for this pin.
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func (p GPIO) setPinCfg(val sam.RegValue8) {
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switch p.Pin {
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case 0:
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sam.PORT.PINCFG0_0 = val
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case 1:
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sam.PORT.PINCFG0_1 = val
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case 2:
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sam.PORT.PINCFG0_2 = val
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case 3:
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sam.PORT.PINCFG0_3 = val
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case 4:
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sam.PORT.PINCFG0_4 = val
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case 5:
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sam.PORT.PINCFG0_5 = val
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case 6:
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sam.PORT.PINCFG0_6 = val
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case 7:
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sam.PORT.PINCFG0_7 = val
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case 8:
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sam.PORT.PINCFG0_8 = val
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case 9:
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sam.PORT.PINCFG0_9 = val
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case 10:
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sam.PORT.PINCFG0_10 = val
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case 11:
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sam.PORT.PINCFG0_11 = val
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case 12:
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sam.PORT.PINCFG0_12 = val
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case 13:
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sam.PORT.PINCFG0_13 = val
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case 14:
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sam.PORT.PINCFG0_14 = val
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case 15:
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sam.PORT.PINCFG0_15 = val
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case 16:
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sam.PORT.PINCFG0_16 = val
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case 17:
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sam.PORT.PINCFG0_17 = val
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case 18:
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sam.PORT.PINCFG0_18 = val
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case 19:
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sam.PORT.PINCFG0_19 = val
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case 20:
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sam.PORT.PINCFG0_20 = val
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case 21:
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sam.PORT.PINCFG0_21 = val
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case 22:
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sam.PORT.PINCFG0_22 = val
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case 23:
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sam.PORT.PINCFG0_23 = val
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case 24:
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sam.PORT.PINCFG0_24 = val
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case 25:
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sam.PORT.PINCFG0_25 = val
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case 26:
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sam.PORT.PINCFG0_26 = val
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case 27:
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sam.PORT.PINCFG0_27 = val
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case 28:
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sam.PORT.PINCFG0_28 = val
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case 29:
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sam.PORT.PINCFG0_29 = val
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case 30:
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sam.PORT.PINCFG0_30 = val
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case 31:
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sam.PORT.PINCFG0_31 = val
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}
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}
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// UART
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var (
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// The first hardware serial port on the SAMD21. Uses the SERCOM0 interface.
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UART0 = &UART{}
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)
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const (
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sampleRate16X = 16
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lsbFirst = 1
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sercomRXPad0 = 0
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sercomRXPad1 = 1
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sercomRXPad2 = 2
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sercomRXPad3 = 3
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sercomTXPad0 = 0 // Only for UART
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sercomTXPad2 = 1 // Only for UART
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sercomTXPad023 = 2 // Only for UART with TX on PAD0, RTS on PAD2 and CTS on PAD3
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)
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// Configure the UART.
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func (uart UART) Configure(config UARTConfig) {
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// Default baud rate to 115200.
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if config.BaudRate == 0 {
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config.BaudRate = 115200
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}
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// enable pins
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GPIO{UART_TX_PIN}.Configure(GPIOConfig{Mode: GPIO_SERCOM})
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GPIO{UART_RX_PIN}.Configure(GPIOConfig{Mode: GPIO_SERCOM})
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// reset SERCOM0
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sam.SERCOM0_USART.CTRLA |= sam.SERCOM_USART_CTRLA_SWRST
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for (sam.SERCOM0_USART.CTRLA&sam.SERCOM_USART_CTRLA_SWRST) > 0 ||
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(sam.SERCOM0_USART.SYNCBUSY&sam.SERCOM_USART_SYNCBUSY_SWRST) > 0 {
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}
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// set UART mode/sample rate
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// SERCOM_USART_CTRLA_MODE(mode) |
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// SERCOM_USART_CTRLA_SAMPR(sampleRate);
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sam.SERCOM0_USART.CTRLA = (sam.SERCOM_USART_CTRLA_MODE_USART_INT_CLK << sam.SERCOM_USART_CTRLA_MODE_Pos) |
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(1 << sam.SERCOM_USART_CTRLA_SAMPR_Pos) // sample rate of 16x
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// Set baud rate
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uart.SetBaudRate(config.BaudRate)
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// setup UART frame
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// SERCOM_USART_CTRLA_FORM( (parityMode == SERCOM_NO_PARITY ? 0 : 1) ) |
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// dataOrder << SERCOM_USART_CTRLA_DORD_Pos;
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sam.SERCOM0_USART.CTRLA |= (0 << sam.SERCOM_USART_CTRLA_FORM_Pos) | // no parity
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(lsbFirst << sam.SERCOM_USART_CTRLA_DORD_Pos) // data order
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// set UART stop bits/parity
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// SERCOM_USART_CTRLB_CHSIZE(charSize) |
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// nbStopBits << SERCOM_USART_CTRLB_SBMODE_Pos |
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// (parityMode == SERCOM_NO_PARITY ? 0 : parityMode) << SERCOM_USART_CTRLB_PMODE_Pos; //If no parity use default value
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sam.SERCOM0_USART.CTRLB |= (0 << sam.SERCOM_USART_CTRLB_CHSIZE_Pos) | // 8 bits is 0
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(0 << sam.SERCOM_USART_CTRLB_SBMODE_Pos) | // 1 stop bit is zero
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(0 << sam.SERCOM_USART_CTRLB_PMODE_Pos) // no parity
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// set UART pads. This is not same as pins...
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// SERCOM_USART_CTRLA_TXPO(txPad) |
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// SERCOM_USART_CTRLA_RXPO(rxPad);
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sam.SERCOM0_USART.CTRLA |= (sercomTXPad2 << sam.SERCOM_USART_CTRLA_TXPO_Pos) |
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(sercomRXPad3 << sam.SERCOM_USART_CTRLA_RXPO_Pos)
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// Enable Transceiver and Receiver
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//sercom->USART.CTRLB.reg |= SERCOM_USART_CTRLB_TXEN | SERCOM_USART_CTRLB_RXEN ;
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sam.SERCOM0_USART.CTRLB |= (sam.SERCOM_USART_CTRLB_TXEN | sam.SERCOM_USART_CTRLB_RXEN)
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// Enable USART1 port.
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// sercom->USART.CTRLA.bit.ENABLE = 0x1u;
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sam.SERCOM0_USART.CTRLA |= sam.SERCOM_USART_CTRLA_ENABLE
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for (sam.SERCOM0_USART.SYNCBUSY & sam.SERCOM_USART_SYNCBUSY_ENABLE) > 0 {
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}
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// setup interrupt on receive
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sam.SERCOM0_USART.INTENSET = sam.SERCOM_USART_INTENSET_RXC
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// Enable RX IRQ.
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//arm.SetPriority(sam.IRQ_SERCOM0, 0xc0)
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arm.EnableIRQ(sam.IRQ_SERCOM0)
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}
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// SetBaudRate sets the communication speed for the UART.
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func (uart UART) SetBaudRate(br uint32) {
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// Asynchronous fractional mode (Table 24-2 in datasheet)
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// BAUD = fref / (sampleRateValue * fbaud)
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// (multiply by 8, to calculate fractional piece)
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// uint32_t baudTimes8 = (SystemCoreClock * 8) / (16 * baudrate);
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baud := (CPU_FREQUENCY * 8) / (sampleRate16X * br)
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// sercom->USART.BAUD.FRAC.FP = (baudTimes8 % 8);
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// sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8);
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sam.SERCOM0_USART.BAUD = sam.RegValue16(((baud % 8) << sam.SERCOM_USART_BAUD_FRAC_MODE_FP_Pos) |
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((baud / 8) << sam.SERCOM_USART_BAUD_FRAC_MODE_BAUD_Pos))
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}
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// WriteByte writes a byte of data to the UART.
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func (uart UART) WriteByte(c byte) error {
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// wait until ready to receive
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for (sam.SERCOM0_USART.INTFLAG & sam.SERCOM_USART_INTFLAG_DRE) == 0 {
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}
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sam.SERCOM0_USART.DATA = sam.RegValue16(c)
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return nil
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}
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//go:export SERCOM0_IRQHandler
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func handleUART0() {
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// should reset IRQ
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bufferPut(byte((sam.SERCOM0_USART.DATA & 0xFF)))
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sam.SERCOM0_USART.INTFLAG |= sam.SERCOM_USART_INTFLAG_RXC
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}
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// I2C on the SAMD21.
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type I2C struct {
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Bus *sam.SERCOM_I2CM_Type
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}
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// Since the I2C interfaces on the SAMD21 use the SERCOMx peripherals,
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// you can have multiple ones. we currently only implement one.
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var (
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I2C0 = I2C{Bus: sam.SERCOM3_I2CM}
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)
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// I2CConfig is used to store config info for I2C.
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type I2CConfig struct {
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Frequency uint32
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SCL uint8
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SDA uint8
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}
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const (
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// Default rise time in nanoseconds, based on 4.7K ohm pull up resistors
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riseTimeNanoseconds = 125
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// wire bus states
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wireUnknownState = 0
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wireIdleState = 1
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wireOwnerState = 2
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wireBusyState = 3
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// wire commands
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wireCmdNoAction = 0
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wireCmdRepeatStart = 1
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wireCmdRead = 2
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wireCmdStop = 3
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)
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const i2cTimeout = 1000
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// Configure is intended to setup the I2C interface.
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func (i2c I2C) Configure(config I2CConfig) {
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// Default I2C bus speed is 100 kHz.
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if config.Frequency == 0 {
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config.Frequency = TWI_FREQ_100KHZ
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}
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// reset SERCOM3
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i2c.Bus.CTRLA |= sam.SERCOM_I2CM_CTRLA_SWRST
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for (i2c.Bus.CTRLA&sam.SERCOM_I2CM_CTRLA_SWRST) > 0 ||
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(i2c.Bus.SYNCBUSY&sam.SERCOM_I2CM_SYNCBUSY_SWRST) > 0 {
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}
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// Set i2c master mode
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//SERCOM_I2CM_CTRLA_MODE( I2C_MASTER_OPERATION )
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i2c.Bus.CTRLA = (sam.SERCOM_I2CM_CTRLA_MODE_I2C_MASTER << sam.SERCOM_I2CM_CTRLA_MODE_Pos) // |
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i2c.SetBaudRate(config.Frequency)
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// Enable I2CM port.
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// sercom->USART.CTRLA.bit.ENABLE = 0x1u;
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i2c.Bus.CTRLA |= sam.SERCOM_I2CM_CTRLA_ENABLE
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for (i2c.Bus.SYNCBUSY & sam.SERCOM_I2CM_SYNCBUSY_ENABLE) > 0 {
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}
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// set bus idle mode
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i2c.Bus.STATUS |= (wireIdleState << sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos)
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for (i2c.Bus.SYNCBUSY & sam.SERCOM_I2CM_SYNCBUSY_SYSOP) > 0 {
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}
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// enable pins
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GPIO{SDA_PIN}.Configure(GPIOConfig{Mode: GPIO_SERCOM})
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GPIO{SCL_PIN}.Configure(GPIOConfig{Mode: GPIO_SERCOM})
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}
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// SetBaudRate sets the communication speed for the I2C.
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func (i2c I2C) SetBaudRate(br uint32) {
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// Synchronous arithmetic baudrate, via Arduino SAMD implementation:
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// SystemCoreClock / ( 2 * baudrate) - 5 - (((SystemCoreClock / 1000000) * WIRE_RISE_TIME_NANOSECONDS) / (2 * 1000));
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baud := CPU_FREQUENCY/(2*br) - 5 - (((CPU_FREQUENCY / 1000000) * riseTimeNanoseconds) / (2 * 1000))
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i2c.Bus.BAUD = sam.RegValue(baud)
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}
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// Tx does a single I2C transaction at the specified address.
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// It clocks out the given address, writes the bytes in w, reads back len(r)
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// bytes and stores them in r, and generates a stop condition on the bus.
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func (i2c I2C) Tx(addr uint16, w, r []byte) error {
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var err error
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if len(w) != 0 {
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// send start/address for write
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i2c.sendAddress(addr, true)
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|
|
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// wait until transmission complete
|
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timeout := i2cTimeout
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for (i2c.Bus.INTFLAG & sam.SERCOM_I2CM_INTFLAG_MB) == 0 {
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|
timeout--
|
|
if timeout == 0 {
|
|
return errors.New("I2C timeout on ready to write data")
|
|
}
|
|
}
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|
|
|
// ACK received (0: ACK, 1: NACK)
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if (i2c.Bus.STATUS & sam.SERCOM_I2CM_STATUS_RXNACK) > 0 {
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return errors.New("I2C write error: expected ACK not NACK")
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|
}
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|
|
|
// write data
|
|
for _, b := range w {
|
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err = i2c.WriteByte(b)
|
|
if err != nil {
|
|
return err
|
|
}
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|
}
|
|
|
|
err = i2c.signalStop()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
if len(r) != 0 {
|
|
// send start/address for read
|
|
i2c.sendAddress(addr, false)
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|
|
|
// wait transmission complete
|
|
for (i2c.Bus.INTFLAG & sam.SERCOM_I2CM_INTFLAG_SB) == 0 {
|
|
// If the slave NACKS the address, the MB bit will be set.
|
|
// In that case, send a stop condition and return error.
|
|
if (i2c.Bus.INTFLAG & sam.SERCOM_I2CM_INTFLAG_MB) > 0 {
|
|
i2c.Bus.CTRLB |= (wireCmdStop << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Stop condition
|
|
return errors.New("I2C read error: expected ACK not NACK")
|
|
}
|
|
}
|
|
|
|
// ACK received (0: ACK, 1: NACK)
|
|
if (i2c.Bus.STATUS & sam.SERCOM_I2CM_STATUS_RXNACK) > 0 {
|
|
return errors.New("I2C read error: expected ACK not NACK")
|
|
}
|
|
|
|
// read first byte
|
|
r[0] = i2c.readByte()
|
|
for i := 1; i < len(r); i++ {
|
|
// Send an ACK
|
|
i2c.Bus.CTRLB &^= 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 |= 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 = sam.RegValue8(data)
|
|
|
|
// wait until transmission successful
|
|
timeout := i2cTimeout
|
|
for (i2c.Bus.INTFLAG & sam.SERCOM_I2CM_INTFLAG_MB) == 0 {
|
|
// check for bus error
|
|
if (sam.SERCOM3_I2CM.STATUS & sam.SERCOM_I2CM_STATUS_BUSERR) > 0 {
|
|
return errors.New("I2C bus error")
|
|
}
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errors.New("I2C timeout on write data")
|
|
}
|
|
}
|
|
|
|
if (i2c.Bus.STATUS & sam.SERCOM_I2CM_STATUS_RXNACK) > 0 {
|
|
return errors.New("I2C write error: expected ACK not NACK")
|
|
}
|
|
|
|
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&(wireIdleState<<sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos)) == 0 &&
|
|
(i2c.Bus.STATUS&(wireOwnerState<<sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos)) == 0 {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errors.New("I2C timeout on bus ready")
|
|
}
|
|
}
|
|
i2c.Bus.ADDR = sam.RegValue(data)
|
|
|
|
return nil
|
|
}
|
|
|
|
func (i2c I2C) signalStop() error {
|
|
i2c.Bus.CTRLB |= (wireCmdStop << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Stop command
|
|
timeout := i2cTimeout
|
|
for (i2c.Bus.SYNCBUSY & sam.SERCOM_I2CM_SYNCBUSY_SYSOP) > 0 {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errors.New("I2C timeout on signal stop")
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (i2c I2C) signalRead() error {
|
|
i2c.Bus.CTRLB |= (wireCmdRead << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Read command
|
|
timeout := i2cTimeout
|
|
for (i2c.Bus.SYNCBUSY & sam.SERCOM_I2CM_SYNCBUSY_SYSOP) > 0 {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errors.New("I2C timeout on signal read")
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (i2c I2C) readByte() byte {
|
|
for (i2c.Bus.INTFLAG & sam.SERCOM_I2CM_INTFLAG_SB) == 0 {
|
|
}
|
|
return byte(i2c.Bus.DATA)
|
|
}
|