Hello and Happy 2010 to all,
I am looking to interface AD9225 (12-bit, 25MHz) to a Blackfin BF533 using the PPI port. Here's the setup I intend to use (only talking about the digital side of things):
- AD9225 driven by external clock (~ 10MHz or higher).
- PPI0-11 are connected to the output of the AD9225.
- AD9225 run from 5V supply but configured for 3.3V output drive.
- ADC data will be transferred to memory via DMA.
- AD9225 Datasheet is here: http://www.analog.com/static/imported-files/Data_Sheets/AD9225.pdf
My questions now are:
- Being a parallel ADC, there's a new set of data availble for read by the DSP every clock cycle (after considering latency and such). The question is, where should the ADC clock be fed to the BF533 for synchronization purposes? should it go to the PPI_CLK pin or should it be used as the Frame Sync by connecting it to the PPI_FS1 pin? The picture attached (from BF533 manual) talks about ADCs with Frame Sync pin, which is not available in the AD9225.
- If it should be connected to the PPI_FS1 pin, what the PPI_CLK should be connected to?
- What is a good method to setup the ADC-to-DMA transfer?
- A low-jitter clock with fast rise and fall times is needed for the ADC as far as I know. Are there any recommendations for ADI products that will do the job? It will have to run from 5V supply same as the ADC. All I found on ADI site run from 3.3V instead.
Thanks in advance,