ADS1298 Wrong ID

Juergen Schramek

Other Parts Discussed in Thread: ADS1298

We are using your ADS1298. In general the system is working fine. But sometimes we read IDReg 0x80 an d we are not able to write (0x40)to Register 9...12. Read is allways 0x00. SO we do not get date on the high 4 channels. Only a hard on/off solve that problem]

over 9 years ago

0 Greg Hupp over 9 years ago

TI__Mastermind 23235 points

Please ensure that you are following the power-on procedure described in the datasheet. If you do not properly start the device, this is a possible behavior (ID register is not read correctly).

0 Juergen Schramek over 9 years ago in reply to Greg Hupp

Prodigy 150 points

After power-on, the ADS1298 works always fine, but when i restart the chip after a reset ( power still is on and PWDN and RESET are connected) sometimes I am not able to read the ID-Register correct.

0 Juergen Schramek over 8 years ago in reply to Greg Hupp

Prodigy 150 points

After some resart of the ADS1298 ( power_down and Reset are connected and set low for 2ms) 4 channels are missing an the ID-Register is 0x00. Only a power Off/on can correct the problem.

0 Brian Pisani over 8 years ago in reply to Juergen Schramek

TI__Mastermind 38745 points

Hey Juergen,

The power-on procedure described in the datasheet needs to be followed even following reset using the RESET/PWDN pin. The timing that is specified is considered to begin after the pin is brought high.

Regards,
Brian Pisani

0 Juergen Schramek over 8 years ago in reply to Brian Pisani

Prodigy 150 points

We can see that if this error happens the drdy-pin is not toggeling after Teset/PWDN goes high
Regards Juergen

0 Brian Pisani over 8 years ago in reply to Juergen Schramek

TI__Mastermind 38745 points

Hey Juergen,

Are you holding the START pin high constantly or do you rely on the START command to begin conversions? If the START pin is low following a reset, conversions will not begin until either the START pin is brought high or the START command is issued.

Brian Pisani

0 Juergen Schramek over 8 years ago in reply to Brian Pisani

Prodigy 150 points

START pin is low, but after reset the mode should be RDATAC mode, so ther schould be a automatic DRDY

0 Brian Pisani over 8 years ago in reply to Juergen Schramek

TI__Mastermind 38745 points

Hey Juergen,

The converter may not be converting while in continuous read mode and vice versa. The START pin and command will control whether the converter is on, and the RDATAC and SDATAC commands will determine whether data can be read with or without command. If the START pin is low after reset and the START command is never issued, DRDY will never toggle. In addition, you will not be able to read registers while in RDATAC mode.

Regards,
Brian Pisani

0 Juergen Schramek over 8 years ago in reply to Brian Pisani

Prodigy 150 points

we start conversation with RDATAC-CMD and START-CMD. If DRDY is low we read out the results. To stop the conversation we activate RESET/PWDN pin for 2ms. Is conversation stopped with RESET-Pin? When we see DRDY toggeling (without any cmd send) after Reset everything is working fine. If we see no DRDY toggeling after Reset we miss 4 channels. Only with power down/up we can finish this error.

0 Brian Pisani over 8 years ago in reply to Juergen Schramek

TI__Mastermind 38745 points

Hey Juergen,

Is the purpose of toggling RESET only to stop conversions? If so, try simply issuing the STOP command instead of resetting the device. Then when you would like to convert again, simply issue the START command.

Regards,
Brian Pisani

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ADS1298 Wrong ID