ADS1299: ID read does not work

Joseph Pathikulangara

Part Number: ADS1299

i have my own board with ADS1299.

set to internal clock. pwdn# and reset# tied to DVdd. start and daisy_in are grounded.

after power is applied, i issue reset command and then start conversion command. the Drdy start pulsing after the start conversion command.

now i issue stop command and try to read the Id register. the part returns zeros. (some other registers do return some '1' bits)

looking at this forum, there is a suggestion that the hardware reset pin MUST be used (rather than software reset - the datasheets suggest either one to be used)

what is the actual situation?

regards,

joseph

over 4 years ago

0 TCT over 4 years ago

TI__Genius 11550 points

Hi Joseph,

Thanks for the post.

Are you connecting the nPWDN and nRESET pins together in your hardware design? If this is the case, then your power-up timing (Figure 76 in the datasheet) using the nRESET pin will not work. You can use the software reset command instead of the hardware reset pin during the device power-up sequence. Please make sure you only issue the RESET command after the VCAP1 reaches 1.1V or higher as shown in the Power-Up Timing Diagram.

Thanks

-TC

0 Joseph Pathikulangara over 4 years ago

Intellectual 270 points

Thanks TC.

I am issuing Reset Command after the VCAP1 voltage reaches 1.1V

the Id is not returned correctly.

is the HW Reset# a MUST for the chip to work?

regards,

joseph

0 TCT over 4 years ago in reply to Joseph Pathikulangara

TI__Genius 11550 points

Hi Joseph,

You can use either the hardware or software reset for the power-up sequence.

Thanks

-TC

+1 Joseph Pathikulangara over 4 years ago in reply to TCT

Intellectual 270 points

Hi TC,

ok thanks.

if i wait/sleep about 2 seconds after the reset command, the Id is returned correctly.

regards,

joseph

0 TCT over 4 years ago in reply to Joseph Pathikulangara

TI__Genius 11550 points

Hi Joseph,

You should only need 18 x t_CLKafter the RESET to start using the device.

Thanks

-TC

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ADS1299: ID read does not work