302 строки
8,8 КиБ
Go
302 строки
8,8 КиБ
Go
// +build sam,atsamd51
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package runtime
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import (
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"device/arm"
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"device/sam"
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"machine"
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)
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type timeUnit int64
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//go:export Reset_Handler
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func main() {
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preinit()
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initAll()
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callMain()
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abort()
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}
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func init() {
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initClocks()
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initRTC()
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initSERCOMClocks()
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initUSBClock()
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initADCClock()
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// connect to USB CDC interface
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machine.UART0.Configure(machine.UARTConfig{})
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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 initClocks() {
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// set flash wait state
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sam.NVMCTRL.CTRLA.SetBits(0 << sam.NVMCTRL_CTRLA_RWS_Pos)
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// software reset
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sam.GCLK.CTRLA.SetBits(sam.GCLK_CTRLA_SWRST)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_SWRST) {
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}
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// Set OSCULP32K as source of Generic Clock Generator 3
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// GCLK->GENCTRL[GENERIC_CLOCK_GENERATOR_XOSC32K].reg = GCLK_GENCTRL_SRC(GCLK_GENCTRL_SRC_OSCULP32K) | GCLK_GENCTRL_GENEN; //generic clock gen 3
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sam.GCLK.GENCTRL3.Set((sam.GCLK_GENCTRL_SRC_OSCULP32K << sam.GCLK_GENCTRL_SRC_Pos) |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL3) {
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}
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// Set OSCULP32K as source of Generic Clock Generator 0
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sam.GCLK.GENCTRL0.Set((sam.GCLK_GENCTRL_SRC_OSCULP32K << sam.GCLK_GENCTRL_SRC_Pos) |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL0) {
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}
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// Enable DFLL48M clock
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sam.OSCCTRL.DFLLCTRLA.Set(0)
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sam.OSCCTRL.DFLLMUL.Set((0x1 << sam.OSCCTRL_DFLLMUL_CSTEP_Pos) |
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(0x1 << sam.OSCCTRL_DFLLMUL_FSTEP_Pos) |
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(0x0 << sam.OSCCTRL_DFLLMUL_MUL_Pos))
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for sam.OSCCTRL.DFLLSYNC.HasBits(sam.OSCCTRL_DFLLSYNC_DFLLMUL) {
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}
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sam.OSCCTRL.DFLLCTRLB.Set(0)
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for sam.OSCCTRL.DFLLSYNC.HasBits(sam.OSCCTRL_DFLLSYNC_DFLLCTRLB) {
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}
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sam.OSCCTRL.DFLLCTRLA.SetBits(sam.OSCCTRL_DFLLCTRLA_ENABLE)
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for sam.OSCCTRL.DFLLSYNC.HasBits(sam.OSCCTRL_DFLLSYNC_ENABLE) {
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}
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sam.OSCCTRL.DFLLVAL.Set(sam.OSCCTRL.DFLLVAL.Get())
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for sam.OSCCTRL.DFLLSYNC.HasBits(sam.OSCCTRL_DFLLSYNC_DFLLVAL) {
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}
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sam.OSCCTRL.DFLLCTRLB.Set(sam.OSCCTRL_DFLLCTRLB_WAITLOCK |
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sam.OSCCTRL_DFLLCTRLB_CCDIS |
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sam.OSCCTRL_DFLLCTRLB_USBCRM)
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for !sam.OSCCTRL.STATUS.HasBits(sam.OSCCTRL_STATUS_DFLLRDY) {
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}
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// set GCLK7 to use DFLL48M as clock source
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sam.GCLK.GENCTRL7.Set((sam.GCLK_GENCTRL_SRC_DFLL << sam.GCLK_GENCTRL_SRC_Pos) |
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(24 << sam.GCLK_GENCTRL_DIVSEL_Pos) |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL7) {
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}
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// Set up the PLLs
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// Set PLL0 at 120MHz
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sam.GCLK.PCHCTRL1.Set(sam.GCLK_PCHCTRL_CHEN |
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(sam.GCLK_PCHCTRL_GEN_GCLK7 << sam.GCLK_PCHCTRL_GEN_Pos))
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sam.OSCCTRL.DPLLRATIO0.Set((0x0 << sam.OSCCTRL_DPLLRATIO_LDRFRAC_Pos) |
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(59 << sam.OSCCTRL_DPLLRATIO_LDR_Pos))
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for sam.OSCCTRL.DPLLSYNCBUSY0.HasBits(sam.OSCCTRL_DPLLSYNCBUSY_DPLLRATIO) {
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}
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// MUST USE LBYPASS DUE TO BUG IN REV A OF SAMD51, via Adafruit lib.
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sam.OSCCTRL.DPLLCTRLB0.Set((sam.OSCCTRL_DPLLCTRLB_REFCLK_GCLK << sam.OSCCTRL_DPLLCTRLB_REFCLK_Pos) |
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sam.OSCCTRL_DPLLCTRLB_LBYPASS)
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sam.OSCCTRL.DPLLCTRLA0.Set(sam.OSCCTRL_DPLLCTRLA_ENABLE)
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for !sam.OSCCTRL.DPLLSTATUS0.HasBits(sam.OSCCTRL_DPLLSTATUS_CLKRDY) ||
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!sam.OSCCTRL.DPLLSTATUS0.HasBits(sam.OSCCTRL_DPLLSTATUS_LOCK) {
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}
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// // Set PLL1 to 100MHz
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sam.GCLK.PCHCTRL2.Set(sam.GCLK_PCHCTRL_CHEN |
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(sam.GCLK_PCHCTRL_GEN_GCLK7 << sam.GCLK_PCHCTRL_GEN_Pos))
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sam.OSCCTRL.DPLLRATIO1.Set((0x0 << sam.OSCCTRL_DPLLRATIO_LDRFRAC_Pos) |
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(49 << sam.OSCCTRL_DPLLRATIO_LDR_Pos)) // this means 100 Mhz?
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for sam.OSCCTRL.DPLLSYNCBUSY1.HasBits(sam.OSCCTRL_DPLLSYNCBUSY_DPLLRATIO) {
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}
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// // MUST USE LBYPASS DUE TO BUG IN REV A OF SAMD51
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sam.OSCCTRL.DPLLCTRLB1.Set((sam.OSCCTRL_DPLLCTRLB_REFCLK_GCLK << sam.OSCCTRL_DPLLCTRLB_REFCLK_Pos) |
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sam.OSCCTRL_DPLLCTRLB_LBYPASS)
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sam.OSCCTRL.DPLLCTRLA1.Set(sam.OSCCTRL_DPLLCTRLA_ENABLE)
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// for !sam.OSCCTRL.DPLLSTATUS1.HasBits(sam.OSCCTRL_DPLLSTATUS_CLKRDY) ||
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// !sam.OSCCTRL.DPLLSTATUS1.HasBits(sam.OSCCTRL_DPLLSTATUS_LOCK) {
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// }
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// Set up the peripheral clocks
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// Set 48MHZ CLOCK FOR USB
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sam.GCLK.GENCTRL1.Set((sam.GCLK_GENCTRL_SRC_DFLL << sam.GCLK_GENCTRL_SRC_Pos) |
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sam.GCLK_GENCTRL_IDC |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL1) {
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}
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// // Set 100MHZ CLOCK FOR OTHER PERIPHERALS
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// sam.GCLK.GENCTRL2.Set((sam.GCLK_GENCTRL_SRC_DPLL1 << sam.GCLK_GENCTRL_SRC_Pos) |
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// sam.GCLK_GENCTRL_IDC |
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// sam.GCLK_GENCTRL_GENEN)
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// for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL2) {
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// }
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// // Set 12MHZ CLOCK FOR DAC
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sam.GCLK.GENCTRL4.Set((sam.GCLK_GENCTRL_SRC_DFLL << sam.GCLK_GENCTRL_SRC_Pos) |
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sam.GCLK_GENCTRL_IDC |
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(4 << sam.GCLK_GENCTRL_DIVSEL_Pos) |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL4) {
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}
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// // Set up main clock
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sam.GCLK.GENCTRL0.Set((sam.GCLK_GENCTRL_SRC_DPLL0 << sam.GCLK_GENCTRL_SRC_Pos) |
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sam.GCLK_GENCTRL_IDC |
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sam.GCLK_GENCTRL_GENEN)
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for sam.GCLK.SYNCBUSY.HasBits(sam.GCLK_SYNCBUSY_GENCTRL0) {
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}
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sam.MCLK.CPUDIV.Set(sam.MCLK_CPUDIV_DIV_DIV1)
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// Use the LDO regulator by default
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sam.SUPC.VREG.ClearBits(sam.SUPC_VREG_SEL)
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// Start up the "Debug Watchpoint and Trace" unit, so that we can use
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// it's 32bit cycle counter for timing.
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//CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
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//DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
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}
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func initRTC() {
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// turn on digital interface clock
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sam.MCLK.APBAMASK.SetBits(sam.MCLK_APBAMASK_RTC_)
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// disable RTC
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sam.RTC_MODE0.CTRLA.ClearBits(sam.RTC_MODE0_CTRLA_ENABLE)
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//sam.RTC_MODE0.CTRLA.Set(0)
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for sam.RTC_MODE0.SYNCBUSY.HasBits(sam.RTC_MODE0_SYNCBUSY_ENABLE) {
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}
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// reset RTC
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sam.RTC_MODE0.CTRLA.SetBits(sam.RTC_MODE0_CTRLA_SWRST)
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for sam.RTC_MODE0.SYNCBUSY.HasBits(sam.RTC_MODE0_SYNCBUSY_SWRST) {
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}
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// set to use ulp 32k oscillator
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sam.OSC32KCTRL.OSCULP32K.Set(sam.OSC32KCTRL_OSCULP32K_EN32K)
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sam.OSC32KCTRL.RTCCTRL.Set(sam.OSC32KCTRL_RTCCTRL_RTCSEL_ULP32K)
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// set Mode0 to 32-bit counter (mode 0) with prescaler 1 and GCLK2 is 32KHz/1
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sam.RTC_MODE0.CTRLA.Set((sam.RTC_MODE0_CTRLA_MODE_COUNT32 << sam.RTC_MODE0_CTRLA_MODE_Pos) |
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(sam.RTC_MODE0_CTRLA_PRESCALER_DIV1 << sam.RTC_MODE0_CTRLA_PRESCALER_Pos) |
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(sam.RTC_MODE0_CTRLA_COUNTSYNC))
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// re-enable RTC
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sam.RTC_MODE0.CTRLA.SetBits(sam.RTC_MODE0_CTRLA_ENABLE)
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for sam.RTC_MODE0.SYNCBUSY.HasBits(sam.RTC_MODE0_SYNCBUSY_ENABLE) {
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}
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arm.SetPriority(sam.IRQ_RTC, 0xc0)
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arm.EnableIRQ(sam.IRQ_RTC)
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}
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func waitForSync() {
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for sam.RTC_MODE0.SYNCBUSY.HasBits(sam.RTC_MODE0_SYNCBUSY_COUNT) {
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}
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}
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// treat all ticks params coming from runtime as being in microseconds
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const tickMicros = 1000
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var (
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timestamp timeUnit // ticks since boottime
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timerLastCounter uint64
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)
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//go:volatile
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type isrFlag bool
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var timerWakeup isrFlag
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const asyncScheduler = false
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// sleepTicks should sleep for d number of microseconds.
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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)
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timerSleep(ticks)
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d -= timeUnit(ticks)
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}
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}
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// ticks returns number of microseconds since start.
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func ticks() timeUnit {
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waitForSync()
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rtcCounter := (uint64(sam.RTC_MODE0.COUNT.Get()) * 305) / 10 // each counter tick == 30.5us
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offset := (rtcCounter - timerLastCounter) // change since last measurement
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timerLastCounter = 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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// ticks are in microseconds
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func timerSleep(ticks uint32) {
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timerWakeup = false
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if ticks < 260 {
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// due to delay waiting for the register value to sync, the minimum sleep value
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// for the SAMD51 is 260us.
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// For related info for SAMD21, see:
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// https://community.atmel.com/comment/2507091#comment-2507091
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ticks = 260
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}
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// request read of count
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waitForSync()
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// set compare value
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cnt := sam.RTC_MODE0.COUNT.Get()
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sam.RTC_MODE0.COMP0.Set(uint32(cnt) + (ticks * 10 / 305)) // each counter tick == 30.5us
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// enable IRQ for CMP0 compare
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sam.RTC_MODE0.INTENSET.SetBits(sam.RTC_MODE0_INTENSET_CMP0)
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for !timerWakeup {
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arm.Asm("wfi")
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}
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}
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//go:export RTC_IRQHandler
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func handleRTC() {
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// disable IRQ for CMP0 compare
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sam.RTC_MODE0.INTFLAG.SetBits(sam.RTC_MODE0_INTENSET_CMP0)
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timerWakeup = true
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}
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func initUSBClock() {
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// Turn on clock(s) for USB
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//MCLK->APBBMASK.reg |= MCLK_APBBMASK_USB;
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//MCLK->AHBMASK.reg |= MCLK_AHBMASK_USB;
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sam.MCLK.APBBMASK.SetBits(sam.MCLK_APBBMASK_USB_)
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sam.MCLK.AHBMASK.SetBits(sam.MCLK_AHBMASK_USB_)
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// Put Generic Clock Generator 1 as source for USB
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//GCLK->PCHCTRL[USB_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK1_Val | (1 << GCLK_PCHCTRL_CHEN_Pos);
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sam.GCLK.PCHCTRL10.Set((sam.GCLK_PCHCTRL_GEN_GCLK1 << sam.GCLK_PCHCTRL_GEN_Pos) |
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sam.GCLK_PCHCTRL_CHEN)
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}
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func initADCClock() {
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// Turn on clocks for ADC0/ADC1.
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sam.MCLK.APBDMASK.SetBits(sam.MCLK_APBDMASK_ADC0_)
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sam.MCLK.APBDMASK.SetBits(sam.MCLK_APBDMASK_ADC1_)
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// Put Generic Clock Generator 1 as source for ADC0 and ADC1.
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sam.GCLK.PCHCTRL40.Set((sam.GCLK_PCHCTRL_GEN_GCLK1 << sam.GCLK_PCHCTRL_GEN_Pos) |
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sam.GCLK_PCHCTRL_CHEN)
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sam.GCLK.PCHCTRL41.Set((sam.GCLK_PCHCTRL_GEN_GCLK1 << sam.GCLK_PCHCTRL_GEN_Pos) |
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sam.GCLK_PCHCTRL_CHEN)
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}
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