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Original question:

ADS1219 pseudo code

ads1219 mode

user4375541
Prodigy 40 points
Other Parts Discussed in Thread: ADS1219
Hi engineer:

I recently used the ads1219 analog-to-digital converter. I have encountered some problems. I want to read the two single-ended analog signals of the ADS1219 through the FPGA. The problem is the difference between single-shot mode and continuous. If I use continuous mode, can I start the continuous conversion by writing the configured data and START/SYNC at the beginning? For my reading of single-ended two-way analog signals, I designed the I2C writing process as follows.

I2C（ WRITE）

1.slave address

2.WREG（40h）

3.configration（Channel,Gain）

4.RREG (read status)

5.START/START/SYNC

I2C（ READ）

1.read DRDY

2.DRDY valid，write RDATA(10H)

3.read data

The above is my read and write process to ADS1219, after writing (1~5 above), then perform the following read operation (read is based on DRDY and then write to RREG to read the converted DATA) .
Is there any problem with this reading and writing process? Can continuous mode read single-ended two-way analog signals? Is this RREG that can be understood as the address of the register at the data to be read?Which mode is recommended to read two single-ended analog signals?

  • 0
    TI__Guru** 113765 points

    Hi User4375541,

    The ADS1219 can only convert one input mux channel at a time.  To convert the 2 separate single-ended measurements, you need to select one input connected to the mux, start the conversion, wait for the conversion to end, then read the result.  Following this sequence you would need to select the other input connected to the mux, start the conversion, wait for the conversion to end, then read the result.  

    To read the conversion result, you would use the RDATA command (the same command is used for both input channels), and the result you receive will depend on which conversion last completed.  If you monitor the DRDY pin, you can usually process the data by polling (or better yet using a falling edge interrupt) this pin for a high to low transition.  This method can be used with continuous mode successfully.  However, if you are monitoring the STATUS register to check for conversion results ready, I would suggest that it may be easier to use single-shot conversion mode to maintain an understanding of which conversion was last completed.  Using single-shot mode will prevent timing issues related to I2C bus timing and when the conversion actually completes.

    Best regards,

    Bob B