I am doing a simple signal measurement using DEO Nano SoC kit interfacing with the terasic High-speed AD/DA card (AD9248) using NIOS processor.
I believe that ADC pin interfacing is fine and the ADC chip is working, however, I face problems about data reading, they are not valid nor stable.,
I think this is because my configuration as follows, but I am not sure:
1. clock for ADC using pll 20Mhz
2. not adding on chip memory for buffer
here uart01.zip is my full code, any help will be appreciated
Could you check with Terasic if they have any example design to get you started.
Mostly Terasic would be able to help to get you started. Example like below case:
Thankyou for your reply.
yes, terasic have some projects about ADC, I learn a lot from their examples.
unfortunately, I only find AD9254 documentation for nios processor application, and the 9254 IP file cannot be modified to AD9248.
from platform design, I set parallel data from ADC as PIO (parallel I/O, width 14 bit) and directly read in c using command "IORD (adc_base, 0)" without on-chip memory as buffer.
if anyone can confirm, do I have to use on-chip memory to store adc data capture before processed in nios? thank you
Hi @Isnan Sorry for the delayed response. Did you find a solution? Have you tested with/without on-chip memory? I think you probably need the on-chip if you are not reading from the NIOS fast enough. Else, your ADC will be overwriting its data even before the NIOS is able to read it.
Unfortunately, I don't find the solution yet. I change the ADC because of limited time. I am using serial ADC with spi interface for now. For first step, it is good enough but of course slower speed. Thank you for the suggestion anyway. I will learn again about parallel ADC to FPGA because I have to use it for final project to catch the speed.