MFRC630 output is DC instead of 13.7 MHz AC

[gaehlers]

Hello

I ported this library from GitHub to my STM32. I understand quite well what it does, and the default configuration seems to make sense. However, when I send the transceive command, the antenna output turns on DC instead of AC 13.7 MHz. There seems to be a problem with the modulation. Also, it stops replying to I2C messages from my STM32.

I checked the quarz, it runs with 27 MHz as it sould. So I guess it is a configuration problem. To me it sounds like the TxSel bits in the TxCon register control the modulation, but none of the values worked as expected.

Thanks for your suggestions.

--Sandro

[gaehlers]

I have to correct my previous statement: It still does reply to I2C messages after sending the transceive() command. I only printed the failed messages, but not the successful ones, which made it look like every single one failed.

However, I still have the problem with the TX output being DC. I tried all values for TxClkMode, that didn't make any difference either.

The most important thing right now: is it a hardware problem, or just software? I should order the PCBs asap, and I have to know if I need to adjust something.

Thanks for you help.

--Sandro

[gaehlers]

Solved! There was a bug in my i2c_read and i2c_write functions: write was performed to a wrong register, but read-back to verify was done from the same wrong address. That's why I didn't notice for so long.