DMA is 8 bit only, have 12 bit ADC data, want to write to 8 bit DAC

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WaMa_286156
Level 5
Level 5
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    I would like to write Data buffered into memory from the  ADC 150,000 sps  rate out the 8 bit dac, capturing a 20khz waveform.  I understand I would either loose the upper 4 bits or the lower 8 bits to do this, unless some extra logic was thrown into the mix.

   

   However, it appears the DMA unit is 8 bits only, and the DAC is 8 bits only.  I would get the upper 4 bits inter-mixed with the lower 8 bits.  Strange dac signals would result.

   

   If I use Dithered dac, I can only to 7,000 sps.

   

   So, any way to get DAC to skip a byte (increment by 2)?

   

   Any work arounds or suggestions?   I guess I could verilog up something, just don't want to go there yet.

   

   I prefer not to use cpu resources, but I'm open to any suggestion at this point.

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