115 строки
2,3 КиБ
Go
115 строки
2,3 КиБ
Go
//go:build stm32f4
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// +build stm32f4
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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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// 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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// stop scan, and clear scan resolution
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stm32.ADC1.CR1.ClearBits(stm32.ADC_CR1_SCAN | stm32.ADC_CR1_RES_Msk)
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// set conversion mode and resolution
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stm32.ADC1.CR1.SetBits(stm32.ADC_CR1_RES_TwelveBit)
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// clear CONT, ALIGN, EXTEN and EXTSEL bits from CR2
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stm32.ADC1.CR2.ClearBits(stm32.ADC_CR2_CONT | stm32.ADC_CR2_ALIGN | stm32.ADC_CR2_EXTEN_Msk | stm32.ADC_CR2_EXTSEL_Msk)
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// set CONT, ALIGN, EXTEN and EXTSEL bits from CR2
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stm32.ADC1.CR2.SetBits(stm32.ADC_CR2_CONT_Single | stm32.ADC_CR2_ALIGN_Right)
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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.ConfigureAltFunc(PinConfig{Mode: PinInputAnalog}, 0)
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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(stm32.ADC_SMPR1_SMP11_Cycles84 << (ch - 10) * stm32.ADC_SMPR1_SMP11_Pos)
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} else {
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stm32.ADC1.SMPR2.SetBits(stm32.ADC_SMPR2_SMP1_Cycles84 << (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 12-bit 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.SMPR1.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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case PC0:
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return 10
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case PC1:
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return 11
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case PC2:
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return 12
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case PC3:
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return 13
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case PC4:
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return 14
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case PC5:
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return 15
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}
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return 0
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}
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