Hi Santosh,
The ADS1282 has default configurations. Pages 36-39 in the datasheet explains the register settings and their reset (default) values. The reset values will be programmed after a power-up or reset occurs.
Some important default settings are:
- Data rate = 1kSPS
- Filter = SINC + FIR (aka LPF) in linear phase mode
- Inputs = AINP1 and AINN1
- PGA Gain = 1
You may want to write to the corresponding registers to change the default settings. For example, you may only want to use the SINC filter to avoid the long settling time of the FIR filter.
IMPORTANT NOTE: Before reading or writing to any of the registers, first send the SDATAC command to exit "the read data continuous mode". In this mode the ADS1282 is ignoring other commands.
To read data for the ADS1282 you will use one of two modes:
- Read Data Continuous - this mode is enabled by default when you reset the device. In this mode you just clock out the data (hold DIN low or send zeros to the ADS1282 on DIN) after /DRDY goes low. You exit this mode by sending SDATAC. If you exit this mode to write to the device registers, then you will need to send RDATAC after configuring the device to enter this mode again.
- Read Data by Command - this mode is enabled when you send SDATAC. This mode requires that you send the RDATA command first, then wait for /DRDY to go low, then finally clock out the data. It requires the extra RDATA command before every conversion is retrieved.
- IMPORTANT NOTE: RDATA must be sent before the next data conversion completes to retrieve the following data. The ADS1282 is different from our other delta-sigma data converters in this regard.
I believe most people use the "Read Data Continuous" mode because it is more convenient.
In summary, choosing the mode that you read data will affect the order of SPI commands. I hope those explanations help!
Best Regards,
Chris
