Need help on how to use ADS1243-HT Analog-to-Digital Converter

Hi Ron,

Welcome to the forum!  This part is really not that difficult to use.  Basically you need to power the device, make sure PWDN is pulled high, configure the device, issue a SELFCAL command and the ADS1243 will start converting.

For me to be a little more specific, I need to know what you are trying to do with the device, what you have connected, and so on.  In other words, what does the finished puzzle look like?  Do you have a schematic you can send me?

Best regards,

Bob B

Thanks for the response Bob.  We are just evaluating this part.  Here is how it is connected.  The analog inputs are tied to various fixed voltages on a resistor ladder.  Why do you say that the device will start converting after issuing the SELFCAL command?  I don't see that in the datasheet.  Here is a guess as to a procedure:

Write appropriate values to SETUP register.  (I suppose I use the WREG command to do this?)
Write appropriate values to MUX register.
Write appropriate values to ACR register.
Run SELFCAL command.
Run SELFOCAL command.
Run SELFGCAL command.
Poll DRDY bit by reading ACR register.  (I do not have enough port pins to hard-wire DRDY to the MCU.)

Does this look like it will work?
Thanks
Ron

Hi Ron,

The device will start converting as soon as you power up the device and it initializes.  This assumes that the master clock is active (either by external clock source on Xin pins as you show, or  by crystal) and the device is not in PDWN (which as you show has PDWN pulled high.)

To set the configuration you would use the WREG command.  As a part of your configuration you will need to set the RANGE bit to 1 in the ACR register because you use a reference voltage greater than 2.5V.

The SELFCAL does both offset calibration and gain calibration, so you don't need to do the individual calibrations.  One thing to note is the SELFCAL requires RANGE set to 0 and PGA set to 1.  It is best to run SELFCAL before setting the registers in this case.

To know when the conversion is complete you will have to RREG command to the ACR register if you do not use the DRDY pin.  After the conversion is complete you can issue the RDATA command to read out the results.

Best regards,

Bob B

Thank you, this is very helpful.  Unfortunately it will be a few weeks before we get our boards made and I get to test with the device.  I'll let you know how it goes.

Hello:

1.  "  As a part of your configuration you will need to set the RANGE bit to 1 in the ACR register because you use a reference voltage greater than 2.5V."

Why do we need to set the RANGE bit to 1 in the ACR register because you use a reference voltage greater than 2.5V? I do not see it on the data sheet.

I set Gain=1. I think I should set RANGE bit to 0 in the ACR registe. ( 0=Full scale input range equal to +-VREF) according to the data sheet.

2. After ( PDWN=1) power on , how long do I need to wait before sending configuration command?

3.  Can you explain how the AD converter use the "ODAC"/offset DAC?

There are two formals for the "ODAC" in the datasheet , one equals 0, the other equals 1. Can you explain?

Thanks

Thanks first.

can you explain the FSR0/1/2? How are they used by the AD converter?

Thanks

Y.L