2020-08-04 09:39 AM
Greetings!
I am new to microprocessors and am using an H7 board, and I have been using the CubeIDE. I have done most the basic/introductory examples, so I understand the basics of how to trigger the DAC with a timer, and how to run a timer in PWM mode, and some basic GPIO stuff.
I have been trying to combine the Timer Triggered DAC output with a PWM signal to create a DAC signal that starts on the falling edge of the PWM pulse and stops on its rising edge. From I have been told, the PWM signal cannot directly trigger the DAC (though I have been struggling to fully understand why), so the next best option would be to synchronize two timers. The master timer will control a PWM signal and the slave will be triggered by the PWM it, which hopefully then can trigger the DAC?
I have spent the last two weeks looking at example videos/documentation/forum posts online and have yet to find a solution that is specifically what I'm looking for. So, I would appreciate any help. Please let me know if this is even possible, and what I can do to get on the right track.
Thank-you!
2020-08-04 10:03 AM
So, you want to trigger the DMA on both edges of the PWM signal? Then probably you might try using center-aligned PWM on TIMx_CH1 with generating CC1IF at both edges (i.e. TIMx_CR1.CMS=0b11), and using that as TRGO (i.e. setting TIMx_CR2.MMS=0b011).
I don't see how looking at videos might help. You may want to look into the Reference Manual (TIM, DAC and probably DMA chapters) instead.
JW
2020-08-04 10:12 AM
In the end, I want to trigger the DAC to start pulling data from the DMA based on the timing of the pulse from a PWM signal. I've been looking at example videos because I've been working with the CubeIDE to configure all my peripherals.