CR95HF: Intermittent Invalid Protocol - 0x83

[ABirj.1]

Hello Folks,

We intermittently see an "invalid protocol - 0x83' error while reading data.

send_cmd 0x04 0x04 0x16 0x00 0x00 0x00

rcv_hdr 0x83 0x00

This happens intermittently and I have not been successful in reproducing the error.

Usually a restart or connect helps to resolve the error.

Any pointers on what is causing the error and how to reproduce it on a testing environment?

Best Regards,

Abhi.

[Brian TIDAL · Accepted solution]

Hi Abhi,

can you provide more information about the firmware being used:

• is it based on RFAL from X-CUBE-NFC3 (or from ST25 Embedded NFC library) or is it a custom firmware implementing the commands from the datasheet?
• do you use SPI or UART interface?
• do you use the IRQ_OUT or SPI polling mechanism for reading response from the CR95HF?
• on MCU side, do you use a RTOS with different tasks accessing the CR95HF?

I suspect that sometimes the SendRcvd command is used while the protocol has been reset to field off.

Can you connect a logic analyser on SPI (CLK, SS, MISO, MOSI) +IRQ_OUT and provide a trace?

Rgds

BT