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deadprogram
132 lines
3.2 KiB
Go
132 lines
3.2 KiB
Go
//go:build stm32u5
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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 bus clock.
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enableAltFuncClock(unsafe.Pointer(stm32.ADC1))
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// Declare VDDA analog supply valid. Without ASV the ADC LDO cannot start.
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stm32.PWR.SVMCR.SetBits(stm32.PWR_SVMCR_ASV)
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// Set ADC12_Common CCR: synchronous clock HCLK/1.
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// ADC12_Common is mapped as ADC_Type; CCR at offset 0x08 = .CR field.
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stm32.ADC12_Common.CR.Set(1 << 16) // CKMODE=01
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// Exit deep power-down mode.
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stm32.ADC1.CR.ClearBits(stm32.ADC_CR_DEEPPWD)
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// Enable internal voltage regulator and wait for LDO ready.
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stm32.ADC1.CR.SetBits(stm32.ADC_CR_ADVREGEN)
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for !stm32.ADC1.ISR.HasBits(stm32.ADC_ISR_LDORDY) {
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}
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// Calibrate ADC (single-ended).
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stm32.ADC1.CR.SetBits(stm32.ADC_CR_ADCAL)
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for stm32.ADC1.CR.HasBits(stm32.ADC_CR_ADCAL) {
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}
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// 12-bit resolution, overwrite DR on overrun.
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stm32.ADC1.CFGR1.Set(stm32.ADC_CFGR1_RES_TwelveBit<<stm32.ADC_CFGR1_RES_Pos |
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stm32.ADC_CFGR1_OVRMOD)
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// Pre-select all channels (PCSEL must be written while ADEN=0).
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stm32.ADC1.PCSEL.Set(0xFFFFF)
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// Clear ADRDY flag, enable ADC, wait for ready.
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stm32.ADC1.ISR.Set(stm32.ADC_ISR_ADRDY)
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stm32.ADC1.CR.SetBits(stm32.ADC_CR_ADEN)
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for !stm32.ADC1.ISR.HasBits(stm32.ADC_ISR_ADRDY) {
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}
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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(config ADCConfig) {
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a.Pin.Configure(PinConfig{Mode: PinInputAnalog})
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ch := a.getChannel()
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// Set sampling time for this channel.
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// Channels 0-9 use SMPR1, channels 10-19 use SMPR2.
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// Each channel uses 3 bits. Default to 36.5 cycles for reliable reads.
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const smpVal = 0x4 // 36.5 ADC clock cycles
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if ch <= 9 {
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pos := uint8(ch) * 3
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stm32.ADC1.SMPR1.ReplaceBits(smpVal, 0x7, pos)
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} else {
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pos := uint8(ch-10) * 3
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stm32.ADC1.SMPR2.ReplaceBits(smpVal, 0x7, pos)
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}
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}
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// Get returns the current value of an ADC pin in the range 0..0xffff.
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func (a ADC) Get() uint16 {
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ch := uint32(a.getChannel())
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// PCSEL already set for all channels in InitADC (must be written while ADEN=0).
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// Set up regular sequence: 1 conversion, channel in SQ1
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// Note: ADC_SQR1_SQ1_Pos (0xC) in the device header is wrong for the 14-bit ADC1/ADC2.
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// RM0456 shows SQ1 at bits [10:6] = position 6.
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stm32.ADC1.SQR1.Set(ch << 6) // L=0 means 1 conversion
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// Start conversion
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stm32.ADC1.CR.SetBits(stm32.ADC_CR_ADSTART)
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// Wait for end of conversion
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for stm32.ADC1.ISR.Get()&stm32.ADC_ISR_EOC == 0 {
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}
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// Read 12-bit result and scale to 16-bit
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result := uint16(stm32.ADC1.DR.Get()) << 4
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return result
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}
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// getChannel returns the ADC1 channel number for a given GPIO pin.
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// STM32U585 ADC1 channel mapping (from datasheet Table 24):
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//
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// PC0=CH1, PC1=CH2, PC2=CH3, PC3=CH4
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// PA0=CH5, PA1=CH6, PA2=CH7, PA3=CH8
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// PA4=CH9, PA5=CH10, PA6=CH11, PA7=CH12
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// PB0=CH13, PB1=CH14
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func (a ADC) getChannel() uint8 {
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switch a.Pin {
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case PC0:
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return 1
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case PC1:
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return 2
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case PC2:
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return 3
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case PC3:
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return 4
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case PA0:
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return 5
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case PA1:
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return 6
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case PA2:
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return 7
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case PA3:
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return 8
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case PA4:
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return 9
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case PA5:
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return 10
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case PA6:
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return 11
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case PA7:
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return 12
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case PB0:
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return 13
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case PB1:
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return 14
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}
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return 0
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}
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