Other Parts Discussed in Thread: SYSBIOS
- Electronics have already been built unfortunately
- Attempting to integrate with a digital to analog converter (DAC) on SPI1 bus.
- The DAC interface is 24-bits per sample, with the /CS line toggling between samples (and not earlier).
- The C6748 SPI TX register is only 16-bits wide.
I am hoping to use 2 different SPIFMT settings to achieve this - the first 16-bits character length with CS_HOLD set to true. The second, an 8-bit character length with CS_HOLD set to false and a wDELAY set to achieve the desired output sample rate to the DAC. I am looking to do this over DMA. My thought is to do a 4-byte DMA transfer to the SPIDAT1 register, with each transfer switching the SPIFMT used with the appropriate data bits filled in.
My concern is whether the hardware is designed/can even do this. The SPI driver included in sysbios does not support this approach, but I won't have a problem making the necessary modifications. However, the fact it wasn't implemented makes me worried that you just can't do this - primarily, that the SPIDAT1 configuration settings will stay linked to the data bits on each word that is submitted by the DMA controller.
Do you think this approach has any chance of working?
