[solved] MFRC522 library and STM32

Not sure if you have seen the other thread about the SPI SS pin, but if you are trying to use the hardware SPI NSS pin to manage CS, that may not work.
If that is the case, try to use some other GPIO pin for CS.

Hi Victor!

Excellent advice. It works after changing the SS pin. The lib also seems to need some tweaking to move some pinMode calls out of the MFRC522 constructor into an init function that is called in setup().
I still have some minor issues but it generally works and I think I’ll start to port this one.

Thanks!

anistor wrote:Hi Victor!

Excellent advice. It works after changing the SS pin. The lib also seems to need some tweaking to move some pinMode calls out of the MFRC522 constructor into an init function that is called in setup().
I still have some minor issues but it generally works and I think I’ll start to port this one.

Thanks!

Glad to let you know the mfrc522 library (https://github.com/miguelbalboa/rfid) was patched and the patch was integrated in master so now it works on stm32f103 boards out of the box.

Adrian

Excellent

Thanks for letting us know

trying to use MFRC522 with my STM32F103 (blue pill).
It compiles fine but the code seems to crash at SPI.beginTransaction(SPISettings(SPI_CLOCK_DIV4, MSBFIRST, SPI_MODE0)); // Set the settings to work with SPI bus

Must be crashing somewhere else

I just added that line to my blink code and it still runs OK

#include "SPI.h"
int counter=0;
void setup() {
// put your setup code here, to run once:
pinMode(PB12,OUTPUT);
Serial.begin(250000);
SPI.beginTransaction(SPISettings(SPI_CLOCK_DIV4, MSBFIRST, SPI_MODE0));

}

bool v=false;
void loop() {

Serial.println(counter++);
// put your main code here, to run repeatedly:
digitalWrite(PB12,v);
delay(50);
v=!v;
}

Strange . Removed all my connections and it doesn’t crash. Will double check again all my RC522 connections

LE: my mistake, I had the “mfrc522.PCD_DumpVersionToSerial(); ” commented out…

Sounds like the code is miss intrepreting the data and perhaps having a buffer overflow

remember the data types are different in ARM than AVR e.g. int is 32 bit, double really is double, “word” may be a different size to what the AVR code thinks it is.

Look carefully at the data types you are reading from the peripheral, you may need to change the variable declarations to explicitly set the size e.g. uint16_t etc

No, It was crashing at that F() macro inside the void MFRC522::PCD_DumpVersionToSerial() {
Moved the #define F(x) x

If i move the F() macro at th begining of my sketch i get compilation errors.

Can we find an workaround, other than replacing all th F() in that library ?

I’d just remove all the F() macros.

Or I guess you could modify WString where the existing F macro is defined