Big problem of pingpong buffer

Started by November 4, 2010
Hello all,
I have a big problem when I am using TMS320C6713.
The data flow is that ADC collects signal and transfer into FPGA, using EDMA, DSP reads the data into ping & pong buffers on chip RAM. I view the waveform of ping & pong in CCS3.3.
First, I use function generator to generate a 100 kHz sine signal.
I find that when EDMA writes to ping, the waveform of ping is not right, but pong is right, as show in picture 1.
When EDMA writes to pong, the waveform of pong is not right, but ping is right, as show in picture 2.
Second, ADC collects signal output from DAC, which is generated by FPGA DDS. The waveforms of ping & pong are all correct.
Thank you!!!!