Required timer count for a number of same frequency different duty cycle PWM signal

Question

Ok, it may look a bit confusing. I am specifically talking about STM32 MCUs, or even more specific, STM32F103C8T6. I did some amount of reading, but could not find the answer to this.

Let's say I want 4 PWM signals each at 50 Hz but all with different duty cycles. In such a case will I need 4 distinct timers, or can I use one timer with 4 channels? I mean can each channel of same timer be configured with different duty cycle?

• DKNguyen: What did you think a channel was for if not this? The answer, by the way, is in the fact that each channel has it's own register.
• muyustan: @DKNguyen I am no sure but maybe for using same timer for both PWM and input capture for example.
• DKNguyen: Fair enough. But then what if there were 4 channels (which there should be on most timers).
• DKNguyen: *Its own count register
• DKNguyen: The count register determines when a channel triggers (for output compare) or what timer count it captures (for input capture).

Answer 1

That's why timers have multiple channels, to generate multiple PWM signals with same timer. If you use multiple separate timers, their output may not be synchronized.

• muyustan: ok, this answers my question, but, what about frequency? is it common for every channel of a timer? or can be different?
• DKNguyen: @muyustan Frequency is common because they all run off the same clock and pre-divider so all channels count at the same time.
• Justme: All channles run with a single timer so they must have identical frequency.