ADS8689: CONVERSION DATA READING ADDRESS

Hello A RAO,

There is no address needed to read conversion data from this ADC,after the CONVST signal is sent to ADC and the conversion is done(tconv_max), the data will be shown on SDO with your SCLK signal.

To identify and solve your issue, we need more information:

• Your timing plot captured by a scope(CONVST/CS,SCLK,SDI and SDO)
• Your schematic for review.
• Your SPI configuration on CPU:     CPOL and CPHASE.

Regards,

Dale

It's hard to see, I only need one timing frame to check which should be similar as figure 3 or 4.

Also,

1. a capacitor(>4.7uF) is missed on REFIO pin. What's the measured voltage on REFIO pin?

2. You are using different ground (GND and ISO_DGND) for AGND and DGND of ADS8689 ADC, where are they connected?

3. What's your SPI configuration(CPOL and CPHASE) on CPU side? Did you change the setting in SDI_CTL_REG register of ADC?

4. Did you see any signal on RVS pin before reading the code (/CS is high)?

5. What's the analog input signal and what 's the code you got when you did the test?

Regards,

Dale