107 строки
2 КиБ
Go
107 строки
2 КиБ
Go
//go:build stm32f103
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package machine
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import (
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"device/stm32"
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"unsafe"
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)
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const (
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Cycles_1_5 = 0x0
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Cycles_7_5 = 0x1
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Cycles_13_5 = 0x2
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Cycles_28_5 = 0x3
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Cycles_41_5 = 0x4
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Cycles_55_5 = 0x5
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Cycles_71_5 = 0x6
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Cycles_239_5 = 0x7
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)
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// InitADC initializes the registers needed for ADC1.
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func InitADC() {
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// Enable ADC clock
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enableAltFuncClock(unsafe.Pointer(stm32.ADC1))
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// set scan mode
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stm32.ADC1.CR1.SetBits(stm32.ADC_CR1_SCAN)
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// clear CONT, ALIGN, EXTRIG and EXTSEL bits from CR2
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stm32.ADC1.CR2.ClearBits(stm32.ADC_CR2_CONT | stm32.ADC_CR2_ALIGN | stm32.ADC_CR2_EXTTRIG_Msk | stm32.ADC_CR2_EXTSEL_Msk)
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stm32.ADC1.SQR1.ClearBits(stm32.ADC_SQR1_L_Msk)
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stm32.ADC1.SQR1.SetBits(2 << stm32.ADC_SQR1_L_Pos) // 2 means 3 conversions
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// enable
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stm32.ADC1.CR2.SetBits(stm32.ADC_CR2_ADON)
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return
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}
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// Configure configures an ADC pin to be able to read analog data.
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func (a ADC) Configure(ADCConfig) {
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a.Pin.Configure(PinConfig{Mode: PinInputModeAnalog})
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// set sample time
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ch := a.getChannel()
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if ch > 9 {
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stm32.ADC1.SMPR1.SetBits(Cycles_28_5 << (ch - 10) * stm32.ADC_SMPR1_SMP11_Pos)
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} else {
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stm32.ADC1.SMPR2.SetBits(Cycles_28_5 << (ch * stm32.ADC_SMPR2_SMP1_Pos))
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}
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return
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}
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// Get returns the current value of a ADC pin in the range 0..0xffff.
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// TODO: DMA based implementation.
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func (a ADC) Get() uint16 {
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// set rank
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ch := uint32(a.getChannel())
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stm32.ADC1.SQR3.SetBits(ch)
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// start conversion
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stm32.ADC1.CR2.SetBits(stm32.ADC_CR2_SWSTART)
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// wait for conversion to complete
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for !stm32.ADC1.SR.HasBits(stm32.ADC_SR_EOC) {
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}
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// read result as 16 bit value
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result := uint16(stm32.ADC1.DR.Get()) << 4
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// clear flag
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stm32.ADC1.SR.ClearBits(stm32.ADC_SR_EOC)
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// clear rank
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stm32.ADC1.SQR3.ClearBits(ch)
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return result
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}
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func (a ADC) getChannel() uint8 {
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switch a.Pin {
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case PA0:
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return 0
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case PA1:
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return 1
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case PA2:
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return 2
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case PA3:
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return 3
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case PA4:
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return 4
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case PA5:
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return 5
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case PA6:
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return 6
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case PA7:
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return 7
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case PB0:
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return 8
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case PB1:
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return 9
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}
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return 0
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}
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