Hm maybe the hat is not recognized automatically and you need to add the overlay in boot/config.txt? Is the green LED lid up?
You could give it a try and add dtoverlay=rpi-tv in boot/config.txt.
You also need to adress some GPU memory for this hat. 128mb are recommended. This can be changed with dietpi-config > 2 : GPU/RAM Memory Split
I guess you need to disable I2C and SPI, isn’t it? 128 MiB GPU memory shouldn’t be required, but the 76 MiB default is sufficient for nearly all cases nowadays.
It’s interesting that the docs do not contain any config step, as if it wouldn’t depend on any dtoverlay, interface or specific pin.
Did you test it on official RPi OS 64-bit, just to rule out a kernel or hardware issue?
According to this post it should be recognized automatically
The biggest change with HAT add-on boards versus older boards designed for models A and B is that the 40W header has 2 special pins (ID_SC and ID_SD) that are reserved exclusively for attaching an ‘ID EEPROM’. The ID EEPROM contains data that identifies the board, tells the Pi how the GPIOs need to be set up and what hardware is on the board. This allows the add-on board to be automatically identified and set up by the Pi software at boot time including loading all the necessary drivers.
But maybe this works only on RPi OS?
And here is written that it communicates via SPI, so it needs to be enabled?! Also 2 I2C pins are in use (I think these are the pins ID_SC and ID_SD for the automatic detection)
We use the same bootloader, kernel and firmware, so whatever works on RPi OS on this level, should work on DietPi the same way.
Since it is not mentioned anywhere that SPI or I2C needs to be enabled (and by default it isn’t either on RPi OS), I guess the EEPROM is read from those two pins before/regardless whether I2C0 is enabled or not (which uses these two pins by default, if enabled), and the auto-configuration implies setting up all GPIO as required. I2C pins can be changed via dtoverlay parameters and the SPI “chip select pins” can be freely set as well, so it makes sense that the HAT configures this to work on the pins required by the HAT, otherwise it would be part of the docs. However, if unsure and as attempt to solve, I’d disable both, I2C and SPI, to match RPi OS defaults.
No spare USB stick/drive or SD card to flash and boot it from? Booting from USB stick/drive is btw recommended anyway, since they survive much longer the constant I/O on the root filesystem.
You do not have force_eeprom_read=0 in your /boot/config.txt, do you? @Jappe
See, this is indeed expected to read HAT’s EEPROM by default from the I2C0 pins, most likely regardless whether I2C0 is enabled on these pins or not: Raspberry Pi Documentation - The config.txt file
Seems like something is broken completely.
Even on rpi os I get the same thing no matter what.
SPI ON
I2C ON
------> chip id invalid
SPI OFF
I2C OFF
-------> chip id invalid
SPI OFF
I2C ON
-------> chip id invalid
SPI ON
I2C OFF
-------> chip id invalid
.
