The device includes a mode where the contents of the internal registers can be read back. This readback mode may be useful as a diagnostic check to verify the serial interface communication between the external controller and the ADC. To use readback mode, follow this procedure:

1. Set the READOUT register bit to 1. This setting disables any further writes to the registers.
2. Initiate a serial interface cycle specifying the address of the register (A7 to A0) whose content has to be read.
3. The device outputs the contents (D7 to D0) of the selected register on the SDOUT pin (pin 64).
4. The external controller can latch the contents at the SCLK falling edge.
5. To enable register writes, reset the READOUT register bit to 0.

The serial register readout works with both CMOS and LVDS interfaces on pin 64.

When READOUT is disabled, the SDOUT pin is in high-impedance state. If serial readout is not used, the SDOUT pin must float.

Figure 8-18 Serial Readout Timing Diagram

A high pulse on the RESET pin is required in the serial interface mode when initialized through a hardware reset. For parallel interface operation, RESET must be permanently tied high.

Figure 8-19 Reset Timing Diagram