PCF8574 I2C configuration for 14.0-CURRENT on a RPi2B
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Date: Sun, 06 Mar 2022 18:11:50 UTC
Greetings,
My RPi2B GPIO header connects to a PCF8574 I2C adapter with these pins:
RPi2B PCF8574
--------------- -------
Pin 2 - +5VDC <-> VCC
Pin 3 - GPIO 2 <-> SDA
Pin 5 - GPIO 3 <-> SCL
Pin 39 - Gnd <-> GND
/boot/loader.conf contains these lines:
root@generic:/boot # cat /boot/loader.conf
# Configure USB OTG; see usb_template(4).
hw.usb.template=3
umodem_load="YES"
# Disable the beastie menu and color
beastie_disable="YES"
loader_color="NO"
gpioiic_load="YES"
and /boot/msdos/config.txt looks like this:
root@generic:/boot # cat /boot/msdos/config.txt
init_uart_clock=3000000
enable_uart=1
kernel=u-boot.bin
kernel7=u-boot.bin
dtoverlay=mmc
/ {
gpioiic0 {
compatible = "i2c-gpio";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gpioiic0>;
scl-gpios = <&gpio2 3 GPIO_ACTIVE_HIGH>;
sda-gpios = <&gpio3 5 GPIO_ACTIVE_HIGH>;
status = "okay";
};
};
Nothing happens:
root@generic:/boot # i2c -sv
dev: /dev/iic0, addr: 0x0, r/w: r, offset: 0x00, width: 8, count: 1
Error opening I2C controller (/dev/iic0): No such file or directory
What's missing? Thank you in advance.
Danke,
--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.