Other Parts Discussed in Thread: ADCPRO
Hi Team,
My customer is trying to put the ADS7953 on the ADS7953-EVM (which sits on the MMB0 board) into the AUTO-2 mode and keeps reading the ADC data for all 16 channels. We expect to see, at least, the channel ID (bit[15:12]) to change from 0~15 repetitively (the 12-bit ADC data can be garbage since ADC inputs are floating right now). BUT they are getting 16'hFFFF always in AUTO-2 mode.
This is what they have done so far:
1. HW side:
a). provide 6V dc to the MMB0 board
b). the USB port of MMB0 board is NOT connected (didn't config the MMB0 board using ADCPro. Q1. Does it need to be configured?)
c). Connect SPI signals from my FPGA board to ADS7953-EVM board (P2.1:SPI_CS_n, P2.3:SPI_SCLK, P2.10:SPI_MOSI, P2.13:SPI_MISO)
2. FPGA SPI access side:
a). power up the devices
b). keep reading/polling ADC CH1 in "manual mode" and check/wait until SPI read data[15:12]==4'h1 (ADC is ready)
SPI TX Data (from FPGA) = 16'h1880
c). program AUTO-2 register (set the last channel in the sequence to 15)
SPI TX Data (from FPGA) = 16'h93C0
d). Change to AUTO-2 mode
SPI TX Data (from FPGA) = 16'h3800
e). Continue operate in a selected mode (Stay in this state, keep sending 16'h0000 forever)
SPI TX Data (from FPGA) = 16'h0000
Observation:
in b). SPI did return the data with channel bits [15:12] set to 4'b0001 (CH1) and my state machine proceeds to e).
in e). The SPI read data is always 16'hFFFF
Q2. Could you tell me what they might be missing?
3. They tried to alter the above sequence by skipping e) and stay in d) forever when d) is reached. The SPI read data is still always 16'hFFFF
Thanks,
Mitchell
