interfacing ads1248 to msp430g2553 using spi

Hi Thulasiram,

I don't have example code yet for the MSP430G2553 and the ADS1248.  There are several aspects to the question of configuration.  The first is setup of the MSP430 for the correct SPI configuration with respect to clock speed, polarity and phase.  The next is deciding on the register values you want to write to the ADS1248.  The third is the actual code sequence to follow to write the configuration.

Before writing to the ADS1248, you need to verify that the communication is correct, and that is best achieved by reading from the part.  Reading and writing are very similar procedures with the difference being the command byte and whether the data is sent or delivered.  I choose to read and write registers in blocks, i.e. I read and write all the registers as one complete transaction.

To read/write a block transfer it is always best to issue SDATAC command first.  The power-up default mode for the ADS1248 is RDATAC mode where the data result is automatically placed to the data output register following the end of the conversion cycle.  This auto update needs to be turned off prior to reading/writing a block of registers as it is possible that the result could be updated in the middle of communication corrupting the data.

The actual process of reading and writing is a sequence of data starting with a command, information regarding which register is first along with the number of registers total that are read/written.  This information is in the datasheet.

What values you acutally write to the registers will depend on the desired configuration.  I would suggest you try the WebBench design page for the ADS1248 and setup your desired configuration and note the acutal register settings needed.  This information can then be applied to your code.

You can see the WebBench tool on the right side of the ADS1248 web page:

http://www.ti.com/product/ads1248

I do have an example for the MSP430G2553 for the ADS1118 that was developed for the Launchpad.  This shows how the MSP430 can be configured for SPI communication and some basic code.  The communication is a little different as far as commands, etc., but is should give you an idea on flow.  This example is in the following post:

http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/t/218787.aspx

Best regards,

Bob B