ADS1298: Can I tie PWDN high?

Kevin Kreger

Part Number: ADS1298

Hello,

I have a 7-channel isolator for isolating my ADS1298, but there are 8 lines connected from our MCU, so one needs to be eliminated. My first reaction was to tie PWDN high as we are just setting it high and leaving it when our board boots. However, my worry is if the ADS1298 hangs (which has not been a problem to date) whether I could always recover by using RESET.

Otherwise, please suggest an alternative like: "RESET and PWDN are both active low so tie them together" I don't think that is an alternative, but...

Thanks in advance,

Kevin

over 8 years ago

0 Ryan Andrews over 8 years ago

TI__Guru 66466 points

Hi Kevin,

Thanks for your post!

You could tie /RESET high with a pull-up resistor. Whenever you wanted to reset the part, you could simply send the RESET SPI command instead. You could also do something similar to the START pin by holding it low and using the START or STOP commands to begin and synchronize conversions.

Best Regards,

0 Kevin Kreger over 8 years ago in reply to Ryan Andrews

Expert 1020 points

Hi Ryan,

Thanks so much for the prompt reply! Tying START low & using the START command sounds best (while keeping RESET, PWDN, & CS as hard controls). Have you tried this?

Thanks

Kevin

0 Ryan Andrews over 8 years ago in reply to Kevin Kreger

TI__Guru 66466 points

Hi Kevin - I have not designed a system around ADS1298 myself, but I do know that is how the device is designed to function. Once you send the START op code, the device will either continue converting until the STOP op code is sent, or the device will complete only a single conversion. This is dependent on the CONFIG4[3] setting which selects between Continuous Conversion Mode and Single-Shot Mode.

Best Regards,

0 Kevin Kreger over 7 years ago in reply to Ryan Andrews

Expert 1020 points

Thanks Ryan!

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ADS1298: Can I tie PWDN high?