ADS1147: How to communicate with multiple ADS1147 device via SPI

Matthew Chen

Part Number: ADS1147
Other Parts Discussed in Thread: SN74LVC1G125

Hi Team,

When using uC communicate with 3 ADS1147 devices using the same SPI with different CS pins for synchronous sampling, the MCU performs to read the data from the specific ADS1147 when its DRDY is valid . The problem happens when the MCU is reading the data from one ADS1147 using SPI, at the same time if another ADS11147 DRDY pin is valid (low), sine these 2 device share the same SCLK, the DRDY pin of second ADS1147 will be rest to High at the first falling edge of SCLK, which there will be a missing read on the second ADS1147. So is there any suggestion to solve this problem? any software or hardware solution is ok.

Matthew chen

3 months ago

0 Bryan Lizon86 3 months ago

TI__Mastermind 37371 points

Hi Matthew Chen,

Can you please post the customer name in the Notes section of the Thread Tracking Toolkit?

-Bryan

0 Matthew Chen 3 months ago in reply to Bryan Lizon86

TI__Intellectual 1130 points

Hi Bryan,

sure, would you get any suggestion on this>

Matthew

0 Bryan Lizon86 3 months ago in reply to Matthew Chen

TI__Mastermind 37371 points

Hi Matthew Chen,

Thanks for providing the requested information

Now as to what the customer is seeing is most likely related to the setting of DRDY high. Even if CS is low, any SCLK sent to the ADC will be seen as a part of the logic sequence that resets the DRDY. One work around is to use a single gate logic (SN74LVC1G125) that is enabled by CS going low and at the same time is gating SCLK when CS is high. This would also require a pull-down on the SCLK pin at the ADS124x.

-Bryan

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ADS1147: How to communicate with multiple ADS1147 device via SPI