44 строки
1,1 КиБ
Go
44 строки
1,1 КиБ
Go
// +build avr,atmega
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package runtime
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import (
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"device/avr"
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"machine"
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)
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func initUART() {
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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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// Sleep for a given period. The period is defined by the WDT peripheral, and is
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// on most chips (at least) 3 bits wide, in powers of two from 16ms to 2s
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// (0=16ms, 1=32ms, 2=64ms...). Note that the WDT is not very accurate: it can
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// be off by a large margin depending on temperature and supply voltage.
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//
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// TODO: disable more peripherals etc. to reduce sleep current.
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func sleepWDT(period uint8) {
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// Configure WDT
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avr.Asm("cli")
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avr.Asm("wdr")
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// Start timed sequence.
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avr.WDTCSR.SetBits(avr.WDTCSR_WDCE | avr.WDTCSR_WDE)
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// Enable WDT and set new timeout
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avr.WDTCSR.SetBits(avr.WDTCSR_WDIE | period)
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avr.Asm("sei")
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// Set sleep mode to idle and enable sleep mode.
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// Note: when using something other than idle, the UART won't work
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// correctly. This needs to be fixed, though, so we can truly sleep.
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avr.SMCR.Set((0 << 1) | avr.SMCR_SE)
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// go to sleep
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avr.Asm("sleep")
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// disable sleep
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avr.SMCR.Set(0)
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}
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