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machine/stm32: fix PWM problem due to register shifting.

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The SVD-generated TIM constants in the STM32 device files have all per-channel
fields shifted by one channel position (e.g., CC1E is at the hardware position
of CC2E, OC1M_Pos is at the OC2M hardware position). This caused Set(), Unset(),
SetInverting(), and interrupt handlers to write to wrong bit positions.

Signed-off-by: deadprogram <ron@hybridgroup.com>
This commit is contained in:
deadprogram
2026-03-18 21:32:47 +01:00
parent 3a00f00f62
commit 82f4fcf2a3
1 changed files with 32 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/machine/machine_stm32_tim.go
+32 -15
View File
@@ -13,6 +13,23 @@ import (
const PWM_MODE1 = 0x6
// Hardware bit positions for TIM registers. The SVD-generated constants
// (stm32.TIM_CCMR1_Output_OC1M_Pos, stm32.TIM_CCER_CC1E, etc.) are
// systematically shifted by one channel in some STM32 device files,
// so we define the correct hardware positions here.
const (
// OC1M[2:0] field position within each CCMR half (bits [6:4]).
tim_CCMR_OCxM_Pos = 4
// Per-channel bit positions within CCER (4 bits per channel).
tim_CCER_CCxE = 0x1 // CCxE at bit 0 of channel group
tim_CCER_CCxP = 0x2 // CCxP at bit 1 of channel group
// Per-channel bit positions within SR, EGR, and DIER (1 bit per channel,
// starting at bit 1 for CC1). Use as: tim_CC1_bit << channel.
tim_CC1_bit = 0x2 // CC1G/CC1IF/CC1IE at bit 1
)
type TimerCallback func()
type ChannelCallback func(channel uint8)
@@ -99,14 +116,14 @@ func (t *TIM) SetMatchInterrupt(channel uint8, callback ChannelCallback) error {
t.OCInterrupt = t.registerOCInterrupt()
// Clear the interrupt flag
t.Device.SR.ClearBits(stm32.TIM_SR_CC1IF << channel)
t.Device.SR.ClearBits(tim_CC1_bit << channel)
// Enable the interrupt
t.OCInterrupt.SetPriority(0xc1)
t.OCInterrupt.Enable()
// Enable the hardware interrupt
t.Device.DIER.SetBits(stm32.TIM_DIER_CC1IE << channel)
t.Device.DIER.SetBits(tim_CC1_bit << channel)
return nil
}
@@ -210,20 +227,20 @@ func (t *TIM) Set(channel uint8, value uint32) {
// Set the PWM to Mode 1 (active below set value, inactive above)
// Preload is disabled so we can change OC value within one update period.
var ccmrVal uint32
ccmrVal |= PWM_MODE1 << stm32.TIM_CCMR1_Output_OC1M_Pos
ccmrVal |= PWM_MODE1 << tim_CCMR_OCxM_Pos
ccmr.ReplaceBits(ccmrVal, 0xFF, offset)
// Set the compare value
ccr.Set(arrtype(value))
// Enable the channel (if not already)
t.Device.CCER.ReplaceBits(stm32.TIM_CCER_CC1E, 0xD, channel*4)
t.Device.CCER.ReplaceBits(tim_CCER_CCxE, 0xD, channel*4)
// Force update
t.Device.EGR.SetBits(stm32.TIM_EGR_CC1G << channel)
t.Device.EGR.SetBits(tim_CC1_bit << channel)
// Reset Interrupt Flag
t.Device.SR.ClearBits(stm32.TIM_SR_CC1IF << channel)
t.Device.SR.ClearBits(tim_CC1_bit << channel)
// Restore interrupts
interrupt.Restore(mask)
@@ -242,10 +259,10 @@ func (t *TIM) Unset(channel uint8) {
ccr.Set(0)
// Disable the hardware interrupt
t.Device.DIER.ClearBits(stm32.TIM_DIER_CC1IE << channel)
t.Device.DIER.ClearBits(tim_CC1_bit << channel)
// Clear the interrupt flag
t.Device.SR.ClearBits(stm32.TIM_SR_CC1IF << channel)
t.Device.SR.ClearBits(tim_CC1_bit << channel)
// Restore interrupts
interrupt.Restore(mask)
@@ -261,10 +278,10 @@ func (t *TIM) SetInverting(channel uint8, inverting bool) {
var val = uint32(0)
if inverting {
val |= stm32.TIM_CCER_CC1P
val |= tim_CCER_CCxP
}
t.Device.CCER.ReplaceBits(val, stm32.TIM_CCER_CC1P_Msk, channel*4)
t.Device.CCER.ReplaceBits(val, tim_CCER_CCxP, channel*4)
}
func (t *TIM) handleUPInterrupt(interrupt.Interrupt) {
@@ -279,29 +296,29 @@ func (t *TIM) handleUPInterrupt(interrupt.Interrupt) {
}
func (t *TIM) handleOCInterrupt(interrupt.Interrupt) {
if t.Device.SR.HasBits(stm32.TIM_SR_CC1IF) {
if t.Device.SR.HasBits(tim_CC1_bit << 0) {
if t.channelCallbacks[0] != nil {
t.channelCallbacks[0](0)
}
}
if t.Device.SR.HasBits(stm32.TIM_SR_CC2IF) {
if t.Device.SR.HasBits(tim_CC1_bit << 1) {
if t.channelCallbacks[1] != nil {
t.channelCallbacks[1](1)
}
}
if t.Device.SR.HasBits(stm32.TIM_SR_CC3IF) {
if t.Device.SR.HasBits(tim_CC1_bit << 2) {
if t.channelCallbacks[2] != nil {
t.channelCallbacks[2](2)
}
}
if t.Device.SR.HasBits(stm32.TIM_SR_CC4IF) {
if t.Device.SR.HasBits(tim_CC1_bit << 3) {
if t.channelCallbacks[3] != nil {
t.channelCallbacks[3](3)
}
}
// Reset interrupt flags
t.Device.SR.ClearBits(stm32.TIM_SR_CC1IF | stm32.TIM_SR_CC2IF | stm32.TIM_SR_CC3IF | stm32.TIM_SR_CC4IF)
t.Device.SR.ClearBits(tim_CC1_bit<<0 | tim_CC1_bit<<1 | tim_CC1_bit<<2 | tim_CC1_bit<<3)
}
func (t *TIM) channelCCR(channel uint8) *arrRegType {