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Question asked by zanzibar on Apr 18, 2011
Latest reply on Apr 19, 2011 by WassimB



I use BF548+external parallel DAC on PPI0.


SCLK= 100Mhz

Output PPI0 clock = 50Mhz


There is a DMA which is transferring from memory arrays to parallel port.


For my test : I have 2 arrays to be transferred : 1 with a sinus signal and 1 with continous signal.


Although I  have a problem of time when I change of arrays : I used DMA by interruption to change of arrays but DSP needs 360ns to reconfigure it and during this period output parallel port does not vary any longer.


So I used DMA by descriptor but time reconfiguration is still 112ns :sinus signal is frozen before being continous.


Can you advice how to do these transfers properly without these additional timings ?