Does your Pi 1B have two mounting holes? (i.e. it's a Pi 1 B version 2.0) as per here:KenLowe wrote: ↑Thu Mar 26, 2020 10:05 amI've just tried this latest release, but it isn't working either. No data on the serial link. I therefore decided to remove the level shifter altogether, and hook the serial comms directly onto the GPIO header. When I do this, I can see valid data being streamed from the RPi. Next step was to use one of my Sundby level shifters in case the issue was specifically with my level shifter. However, I'm seeing the same issue with that level shifter too. No data on the serial link.
https://www.raspberrypi-spy.co.uk/2012/ ... revisions/
Can you try the following:
- Edit config.txt to switch over to the debug kernel
- Remove the level shifter
- Capture a complete log of the Pi booting
Then post that log here, it might show something unexpected.
That's very strange, as this is one of the exact combinations we tested at ABUG.KenLowe wrote: ↑Thu Mar 26, 2020 10:05 amAs I mentioned earlier, one of the 245s on the level shifter board is definitely running hotter when hooked up to the RPi Model B. This is the level shifter for the control and address signals. I'm not sure why this is happening? The same level shifters work fine with the RPi 3B.
It does suggest a conflict is occurring.
Have you double checked the header adapter you made for a short?
The only other thing I can imagine is that the Pi is damaged (a shorted GPIO) and the extra current draw when the level shifter is attached is preventing it from booting. When a GPIO is damaged, often there is a low resistance path to either 0V or 3V3, typically < 100R. Can you go around each of the GPIO pins and check the resistance.