9eaa6a7d7f
The default priority is 0 (highest) which is reserved by the SoftDevice. For normal operation the exact priority level doesn't matter, only the relative priority matters. So this change makes the code compatible with the SoftDevice without actually changing the behavior.
105 строки
2,2 КиБ
Go
105 строки
2,2 КиБ
Go
// +build nrf
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package runtime
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import (
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"device/arm"
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"device/nrf"
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"machine"
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)
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type timeUnit int64
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const tickMicros = 1024 * 32
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//go:linkname systemInit SystemInit
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func systemInit()
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//go:export Reset_Handler
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func main() {
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systemInit()
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preinit()
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initAll()
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mainWrapper()
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abort()
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}
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func init() {
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machine.UART0.Configure(machine.UARTConfig{})
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initLFCLK()
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initRTC()
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}
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func initLFCLK() {
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if machine.HasLowFrequencyCrystal {
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nrf.CLOCK.LFCLKSRC = nrf.CLOCK_LFCLKSTAT_SRC_Xtal
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}
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nrf.CLOCK.TASKS_LFCLKSTART = 1
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for nrf.CLOCK.EVENTS_LFCLKSTARTED == 0 {
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}
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nrf.CLOCK.EVENTS_LFCLKSTARTED = 0
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}
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func initRTC() {
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nrf.RTC1.TASKS_START = 1
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arm.SetPriority(nrf.IRQ_RTC1, 0xc0) // low priority
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arm.EnableIRQ(nrf.IRQ_RTC1)
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}
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func putchar(c byte) {
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machine.UART0.WriteByte(c)
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}
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func sleepTicks(d timeUnit) {
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for d != 0 {
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ticks() // update timestamp
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ticks := uint32(d) & 0x7fffff // 23 bits (to be on the safe side)
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rtc_sleep(ticks) // TODO: not accurate (must be d / 30.5175...)
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d -= timeUnit(ticks)
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}
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}
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var (
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timestamp timeUnit // nanoseconds since boottime
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rtcLastCounter uint32 // 24 bits ticks
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)
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// Monotonically increasing numer of ticks since start.
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//
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// Note: very long pauses between measurements (more than 8 minutes) may
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// overflow the counter, leading to incorrect results. This might be fixed by
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// handling the overflow event.
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func ticks() timeUnit {
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rtcCounter := uint32(nrf.RTC1.COUNTER)
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offset := (rtcCounter - rtcLastCounter) & 0xffffff // change since last measurement
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rtcLastCounter = rtcCounter
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timestamp += timeUnit(offset) // TODO: not precise
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return timestamp
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}
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//go:volatile
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type isrFlag bool
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var rtc_wakeup isrFlag
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func rtc_sleep(ticks uint32) {
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nrf.RTC1.INTENSET = nrf.RTC_INTENSET_COMPARE0
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rtc_wakeup = false
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if ticks == 1 {
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// Race condition (even in hardware) at ticks == 1.
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// TODO: fix this in a better way by detecting it, like the manual
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// describes.
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ticks = 2
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}
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nrf.RTC1.CC[0] = (nrf.RTC1.COUNTER + nrf.RegValue(ticks)) & 0x00ffffff
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for !rtc_wakeup {
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arm.Asm("wfi")
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}
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}
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//go:export RTC1_IRQHandler
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func handleRTC1() {
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nrf.RTC1.INTENCLR = nrf.RTC_INTENSET_COMPARE0
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nrf.RTC1.EVENTS_COMPARE[0] = 0
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rtc_wakeup = true
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}
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