I'm trying to set TIM2 in PWM mode, but I'm getting weird results. CH1 to CH4 are enabled but CH3 on PA2 shows no output no matter I do. The weird thing happens when I try to remap TIM2. There are three remap options, Remap2 is the one I'm interested in:
No remap: CH1=PA0, CH2=PA1, CH3=PA2, CH4=PA3 => no output on CH3(PA2)
Remap1: CH1=PA2, CH2=PA3, CH3=PA15, CH4=PB3 => no output on CH1(PA2) and CH3(PA15)
Remap2: CH1=PA0, CH2=PA1, CH3=PB10, CH4=PB11 => no output on CH1(PA0), CH2(PA1) and CH3(PB10)
Remap3: CH1=PA15, CH2=PB3, CH3=PB10, CH4=PB11 => no output on CH2(PB3) and CH3(PB10)
All GPIO ports are configured correctly, CNF=AF and MODE=OUT. TIM2 clock = 36MHz. Tried lower clock but same result. Tried enabling both TIM2 and TIM3 four PWM channels, no remapping. Got no signal out on CH3 on both timers. Tried another Blue Pill, same result. Tested the GPIO ports PA2 and PB0 and they are both ok.
Here is the code I'm using:
ldr r0, = TIM2 @ APB1 Clock - 36MHz
ldr r1, = 0
str r1, [r0, #TIMx_PSC] @ Clock/Prescaler
ldr r1, = 256
str r1, [r0, #TIMx_ARR] @ Count-Down value for timer
ldr r1, = 128 @ Output Compare preload value
str r1, [r0, #TIMx_CCR1] @ CH1
str r1, [r0, #TIMx_CCR2] @ CH2
str r1, [r0, #TIMx_CCR3] @ CH3
str r1, [r0, #TIMx_CCR4] @ CH4
ldr r1, = 6<<OC2M | 1<<OC2PE | 6<<OC1M | 1<<OC1PE
str r1, [r0, #TIMx_CCMR1] @ CH1 & CH2 PWM Mode1
ldr r1, = 6<<OC4M | 1<<OC4PE | 6<<OC3M | 1<<OC3PE
str r1, [r0, #TIMx_CCMR2] @ CH3 & CH4 PWM Mode1
ldr r1, = 1<<CC4E | 1<<CC3E | 1<<CC2E | 1<<CC1E
str r1, [r0, #TIMx_CCER] @ CH1 to CH4 Enable
ldr r1, = 3<<CMS
str r1, [r0, #TIMx_CR1]
dsb
ldr r1, [r0, #TIMx_CR1]
orr r1, #1<<CEN @ Counter Enable
str r1, [r0, #TIMx_CR1]
