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DMA request from external input signal

Question asked by dumee.gilles on Apr 16, 2013
Latest reply on Apr 29, 2013 by Clive One
I have an input 8 bits parallel bus, with a CLK signal connected to GPIOs. The frequency is 1MHz. I need to configure an automatic DMA transfert from the 8 bits GPIO to a memory buffer (dual buffer mode would be great).
To acheive this, I started to configure a timer to request DMA transferts on each CLK rising edge, with input capture mode. The timer is correctly copying counter in CR1 on rising edge, and DMA is correctly transfering data when I manually initiate a tranfert. But I can't have the timer requesting the DMA transfert.

The TIM1 is configured in Input capture mode on TI1 connected to CH1, with CC1E, CC1DE bits and CCS1 = '01', and CEN bit in CR.
The DMA2 stream 1 is configured as memory to memory mode (for the tests, I don't use GPIO input, just a buffer copy) : DIR = '10', MINC, PINC, PL = '10', channel 6, NDTR = 4, PAR and M0AR configured with my buufers addresses.

Do somebody has a sample source code to do this? I can't find any on google. Is there another solution without timers?

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