Tool/software:
Hello,
I have a custom board with a ADS8681 ADC. The board has the SPI interface wired like figure 7-25 in the data sheet where RST is pulled to 3.3V and RVS is not connected. The board is set for internal reference and 4.096V is measured on both REFIO and REFCAP with 10uF caps on each. 5V powers AVDD and 3.3V powers DVDD. The SPI clock is 10MHz and I'm using the default mode 0, clocking sdi on the rising edge of sclk and the data should be clocked out on the falling edge of sclk after the read command is sent, followed by a NOP. The SDI data is phase shifted by 90degrees so that when the sclk rising edge occurs, the sdi data is stable. To set address x14, I send xD814000B (0-5V inp range) and to read back the register I send xC8140000, followed by a NOP cmd, x00000000. The following screen shots shows the sclk, sdi, sdo and convert/cs pins. Do I have the op codes wrong?spiCmds.pdf Looks like the write cmd should be x"D4xxYYYY", but I still get the same results.
