Start/stop control mode is a gate-control mode used to start and stop conversions. Conversions are started by taking the START pin high or, if conversions are controlled through SPI operation, by writing 1b to the START bit of the CONTROL register. Preclear the CONTROL register by writing 00h before setting the START bit. Conversions continue until stopped by taking the START pin low, or by writing 1b to the STOP bit through SPI operation. DRDY is driven high at conversion start and is driven low when each conversion data are ready. If START is taken low or 1b is written to the STOP bit while conversions are in progress, the ongoing conversion finishes as normal and then stops. (See Figure 6-4 for detailed START timing).

To restart an ongoing conversion, pulse START low to high, or write 1b to the START bit a second time. Figure 8-26 illustrates the START and DRDY operation. If conversions are stopped in standby mode, DRDY returns high three clock cycles after falling low, otherwise DRDY remains low until being forced high at the eighth SCLK edge during conversion data readout. If data are not read, DRDY remains low and pulses high just before the next DRDY falling edge.