Hi,
I have already seen that. It happened with newer Linux kernel and SPI driver that controls by default GPIO8 for SPI0 CS0 and GPIO7 for SPI0 CS1 (e.g modinfo spidev: v5.5.61).
There is a conflict with the ST25R NFC demo that uses ST25R_INT_PIN on GPIO7 as interrupt line between the reader and the microcontroller.
To overcome this, configure the SPI driver to control a different GPIO than GPIO7 for the Chip Select signal.
This can be done with the dtoverlay command.
$ dtoverlay -a ; list all overlay available
$ dtoverlay -h spi0-1cs
Name: spi0-1cs
Info: Only use one CS pin for SPI0
Usage: dtoverlay=spi0-1cs,<param>=<val>
Params: cs0_pin GPIO pin for CS0 (default 8)
no_miso Don't claim and use the MISO pin (9), freeing
it for other uses.
Edit the boot configuration to use this overlay, add the following line:
$ sudo /boot/config.txt
dtoverlay=spi0-1cs
$ reboot
The parameter cs0_pin may be needed in case the driver assigns CE0 to another pin.
e.g. dtoverlay spi0-1cs,cs0_pin=6
Inspect the GPIO configuration
See http://wiringpi.com and use their convenient tool to inspect the GPIOs:
See http://wiringpi.com/ and use their convenient tool to inspect the GPIO:
$ gpio readall
+-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| 2 | 8 | SDA.1 | IN | 1 | 3 || 4 | | | 5v | | |
| 3 | 9 | SCL.1 | IN | 1 | 5 || 6 | | | 0v | | |
| 4 | 7 | GPIO. 7 | IN | 1 | 7 || 8 | 1 | IN | TxD | 15 | 14 |
| | | 0v | | | 9 || 10 | 1 | IN | RxD | 16 | 15 |
| 17 | 0 | GPIO. 0 | IN | 0 | 11 || 12 | 0 | IN | GPIO. 1 | 1 | 18 |
| 27 | 2 | GPIO. 2 | IN | 0 | 13 || 14 | | | 0v | | |
| 22 | 3 | GPIO. 3 | IN | 0 | 15 || 16 | 0 | IN | GPIO. 4 | 4 | 23 |
| | | 3.3v | | | 17 || 18 | 0 | IN | GPIO. 5 | 5 | 24 |
| 10 | 12 | MOSI | ALT0 | 0 | 19 || 20 | | | 0v | | |
| 9 | 13 | MISO | ALT0 | 0 | 21 || 22 | 0 | IN | GPIO. 6 | 6 | 25 |
| 11 | 14 | SCLK | ALT0 | 0 | 23 || 24 | 1 | OUT | CE0 | 10 | 8 |
| | | 0v | | | 25 || 26 | 0 | IN | CE1 | 11 | 7 | <= *: Check that 'CE1' GPIO pin 7 shows direction 'IN', to receive interrupt signal
| 0 | 30 | SDA.0 | IN | 1 | 27 || 28 | 1 | IN | SCL.0 | 31 | 1 |
| 5 | 21 | GPIO.21 | IN | 1 | 29 || 30 | | | 0v | | |
| 6 | 22 | GPIO.22 | IN | 1 | 31 || 32 | 0 | IN | GPIO.26 | 26 | 12 |
| 13 | 23 | GPIO.23 | IN | 0 | 33 || 34 | | | 0v | | |
| 19 | 24 | GPIO.24 | IN | 0 | 35 || 36 | 0 | IN | GPIO.27 | 27 | 16 |
| 26 | 25 | GPIO.25 | IN | 0 | 37 || 38 | 0 | IN | GPIO.28 | 28 | 20 |
| | | 0v | | | 39 || 40 | 1 | IN | GPIO.29 | 29 | 21 |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
*: Check that 'CE1' GPIO pin 7 shows direction 'IN', to receive interrupt signal
Hope this helps.
Br,
Jasper
