Hi,
I am thinking of interfacing ADS4122 to TMS320C6748 DSP for an IF application. It is desirable to sample at about 20~25MHz, 12bit.
The data will be sampled at 20MHz, continuously stream. If we could use DMA, a repeated transfer with DMA buffer size of 1024 (that's about 50us) will be great. Upon DMA interrupt of 1024pts, we'd like to FFT 1024pts using the DSPLIB, I think the FFT may complete within a short 15kcycles (32us if 456MHz?).
From wiki, it seems possible for the uPP interface to achieve this data transfer rate, possible upto 60MSPS for 12b ADC.
| Mode | Theoretical (MB/s) | Realistic (MB/s) |
| 1 Ch, 8-bit | 75 | 60 |
| 1 Ch, 16-bit | 150 | 120 |
I would to find out from here that,
1) Is my setup realistic? Can the C6748 interface to ADS4122 @ 20MSPS via DMA?
2) Will 1024pts FFT operation be fast enough and complete within such short period (32us)?
3) Is the internal RAM sufficient, as the data block is small size? Do you think if I need to include LPDDR SDRAM?
I am targeting a battery operated device, so power consumption is the main concern; thus limit the processor. I think the next choice may be FPGA, but I prefer not to go that path.
Thanks and regards,
Shanguo