ANT7-T-ST25DV04K + CMWX1ZZABZ-078 (STM32L0) I2C read issues

[sid1]

We are trying to interface ANT7-T-ST25DV04K and CMWX1ZZABZ-078 (MuRata LoRaWAN module that has STM32L0). When we read the NFC chip using I2C by the host processor STM32L0 (in LoRaWAN Module), we are reading garbage data (corrupted). However if we use a nucleo STM32L4 dev board to read the NFC, we don't see any issues. Not sure if why L0 does not work?

We tried I2C pull ups and all of them are good. There are other I2C sensors on the same bus, we do not see any issues. Any input is appreciated.

[JL. Lebon · Accepted solution]

Hello,

My first advice would have been to check the pull-up resistors, as there is no pull-up resistors on the ANT7, but it looks like you already did this.

What do you mean exactly by "we are reading garbage data" ?

Do you receive some corrupted data ? Or do you receive some Nacks ? Or anything else ?

Would it be possible for you to capture an I2C frame from L0 to ST25DV with an oscilloscope and share it ? It would help to see if there is any issue on the I2C bus.

Best regards.

[sid1]

Hi JL. Lebon,

Please see more info from our team member on this issues:

https://community.st.com/s/question/0D53W00001Z87W6SAJ/issue-with-getting-proper-data-payload-out-of-st25dv-via-i2c-after-writing-to-it-via-nfc

[Ulysses HERNIOSUS]

Issue is resolved as per referenced ticket - competing I2C slaves.