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Create One-Pulse waveforms repetitive possible? (without interrupt?)

Question asked by bil.til on Jan 29, 2012
Hi,
I have a clock signal in the range of 10MHz.

In every clock cycle (100nsec long) I would like to create a strobe signal, typically 20nsec long, and exact point of the strobe should be variable.

My Clock is produced as PWM by Timer 3, Timer 3 Master mode is set to Update event (TIM3_CR2=0x20, so that MMS= 4).

 I first thought, this might work with the one-pulse mode, e. g. for Timer 1 (I programmed TIM1_CR1 to 0x98, so that OPM=1). Further Timer 1 is operating in Slave mode triggered by Timer 3 in Reset mode (TIM1_SMCR= 0x24 - 2 selects Trigger through TIM3, 4 selects Reset Mode). In description of TIM1_SMCR it says "100: Reset Mode - Rising edge of the selected trigger input reinitializes the counter and generates an update of the registers". I hoped that this would also concern the "One-Pulse functionality". It would really be great if this worked (the flexibility of the timer machine in this controller really is fantastic) - but unfortunately it does not in my testing. Or anybody has some hint, anything which I might have forgotten?

I can create one single pulse like this - but it does NOT repeat / reset with the reset event.

Now instead of the strobe pulse I use a "strobe edge" - this works with this reset mode and standard PWM setting - just I liked the "1-pulse" method too much, therefore my question, whether perhaps somebody has experience in this.

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