JAJSIU8B June 2015 – April 2020 ADS131E08S
The RDATAC command enables read data continuous mode. In this mode, conversion data are retrieved from the device without the need to issue subsequent RDATA commands. This mode places the conversion data in the output register with every DRDY falling edge so that the data can be shifted out directly. Shift out all data from the device before data are updated with a new DRDY falling edge to avoid losing data. The read data continuous mode is the default mode of the device.
Figure 40 shows the ADS131E08S data output protocol when using RDATAC mode.
NOTE:X SCLKs = (N bits)(8 channels) + 24 bits. N-bit is dependent upon the DR[2:0] registry bit settings (N = 16 or 24).
RDATAC mode is stopped by the stop read data continuous (SDATAC) command. If the device is in RDATAC mode, an SDATAC command must be issued before any other commands can be sent to the device. There are no SCLK rate restrictions for this command. However, subsequent data retrieval SCLKs or the SDATAC command must wait at least 4 tCLK cycles for the command to execute. RDATAC timing is shown in Figure 41. There is a keep out zone of 4 tCLK cycles around the DRDY pulse where this command cannot be issued in. If no data are retrieved from the device and CS is held low, a high-to-low DOUT transition occurs synchronously with DRDY. To retrieve data from the device after the RDATAC command is issued, make sure either the START pin is high or the START command is issued. Figure 41 shows the recommended way to use the RDATAC command. Read data continuous mode is ideally-suited for applications such as data loggers or recorders where registers are set one time and do not need to be reconfigured.