PWM TIM8_CH2 PC7 Not Working (50%)

[kzawada]

Posted on November 05, 2010 at 21:29

PWM TIM8_CH2 PC7 Not Working (50%)

[Tesla DeLorean]

Posted on May 17, 2011 at 14:14

I think this for TIM4 is workable, haven't tried TIM8

      /* Time base configuration */       TIM_TimeBaseStructure.TIM_Period = i16uPeriod - 1; // 0 - (Period - 1) = Period       TIM_TimeBaseStructure.TIM_Prescaler = i16uPrescalerValue; // Already -1 applied       TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;       TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;       TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);         /* PWM1 Mode configuration: Channel2 - 50% */       TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;       TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;       TIM_OCInitStructure.TIM_Pulse = i16uPeriod / 2; // 50%       TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;           TIM_OC2Init(TIM4, &TIM_OCInitStructure);       TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);         TIM_OC2Init(TIM4, &TIM_OCInitStructure);            TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);            TIM_ARRPreloadConfig(TIM4, ENABLE);       /* TIM4 enable counter */       TIM_Cmd(TIM4, ENABLE);

[kzawada]

Posted on May 17, 2011 at 14:14

It looks like the counter and the reloading is working just great from the Keil uVision tools.  However, it looks like TIM8_CH2 is not connected to the actual pin (PC7).

How could I trace if the pin (PC7) is getting connected to TIM8_CH2.  I can see that if I use PC7 as standard GPIO output pin I can toggle it easily.   For some reason the mapping that connects TIM8_CH2 to PC7 is missing.  I don't see anything obvious, but it might seem to be something in AFIO.  I have already enabled the AFIO clock. The register values are the following:

[Tesla DeLorean]

Posted on May 17, 2011 at 14:14

I don't have a high density part, I'd be half temped to remap TIM3 on to PC7 and try that. TIM8 should connect right up on your part as best I can tell from here.

[sonhai26988]

Posted on May 17, 2011 at 14:14

Can you help me?

The Timer 8 is not running. the TIM8_CNT not count...

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[kzawada]

Posted on May 17, 2011 at 14:14

Needed to add the following line to connect TIM8_CH2 to PC7:

TIM_CtrlPWMOutputs(TIM8, ENABLE);