The CS pins for each SPI interfaces are declared in Device Tree. The defaults are GPIO8 and GPIO7 for SPI0.0 and SPI0.1. You can change them using a dtoverlay:So to enable SPI0 (which uses GPIOs 9-11), with 2 CS lines on GPIOs 3 and 4, put the following in config.txt:Note that although you'll see many DT parameters called "something-pin", they are actually GPIO numbers. In my example, GPIO 3 is on pin 5 and GPIO 4 is on pin 7. The pinctrl utility can help you find thiungs on the 40-pin header:
Code:
$ dtoverlay -a | grep -E "spi[0-9]-[0-9]" spi0-0cs spi0-1cs spi0-2cs spi0-3cs spi1-1cs spi1-2cs spi1-3cs spi2-1cs spi2-1cs-pi5 spi2-2cs spi2-2cs-pi5 spi2-3cs spi3-1cs spi3-1cs-pi5 spi3-2cs spi3-2cs-pi5 spi4-1cs spi4-2cs spi5-1cs spi5-1cs-pi5 spi5-2cs spi5-2cs-pi5 spi6-1cs spi6-2cs$ dtoverlay -h spi0-2csName: spi0-2csInfo: Change the CS pins for SPI0Usage: dtoverlay=spi0-2cs,<param>=<val>Params: cs0_pin GPIO pin for CS0 (default 8) cs1_pin GPIO pin for CS1 (default 7) no_miso Don't claim and use the MISO pin (9), freeing it for other uses.Code:
dtoverlay=spi0-2cs,cs0_pin=3,cs1_pin=4Code:
$ pinctrl -p 1: 3v3 2: 5v 3: a3 pu | hi // GPIO2 = SDA1 4: 5v 5: a3 pu | hi // GPIO3 = SCL1 6: gnd 7: no pu | -- // GPIO4 = none 8: no pd | -- // GPIO14 = none 9: gnd10: no pd | -- // GPIO15 = none11: op dh pd | hi // GPIO17 = output12: op dh pd | hi // GPIO18 = output13: no pd | -- // GPIO27 = none14: gnd15: no pd | -- // GPIO22 = none16: no pd | -- // GPIO23 = none17: 3v318: no pd | -- // GPIO24 = none19: a0 pn | lo // GPIO10 = SPI0_MOSI20: gnd21: a0 pn | lo // GPIO9 = SPI0_MISO22: no pd | -- // GPIO25 = none23: a0 pn | lo // GPIO11 = SPI0_SCLK24: op dh pu | hi // GPIO8 = output25: gnd26: op dh pu | hi // GPIO7 = output27: ip pu | hi // GPIO0 = input28: ip pu | hi // GPIO1 = input29: no pu | -- // GPIO5 = none30: gnd31: no pu | -- // GPIO6 = none32: no pd | -- // GPIO12 = none33: no pd | -- // GPIO13 = none34: gnd35: a0 pd | lo // GPIO19 = SPI1_MISO36: op dh pd | hi // GPIO16 = output37: no pd | -- // GPIO26 = none38: a0 pd | lo // GPIO20 = SPI1_MOSI39: gnd40: a0 pd | lo // GPIO21 = SPI1_SCLKStatistics: Posted by PhilE — Fri Mar 22, 2024 12:47 pm