1 - 7 Mar '21
- Time to start documenting the software development for the Raspberry Pi 4 (3).
- Back ordered semaphores may be available in April!
- Rebuilding the Pi fan board to make room for the DSI ribbon cable.
- Updated the sitemap generator software.
- With Raspberry Pi 4/AdaFruit updates (?) now the library items don't work to support the 16-channel PWM HAT/Bonnets!
- Excellent help from AdaFruit forum admin. Forced a package update.
- Updated both TechSmith tools.
- Back to the fan. Version #2 of the hardware. Need to clean-up the library. I have forgotten how what I did before works.
- Having read some of the IO Pi Plus HAT documentation, need to do some redesign, move some wires around.
The IO Pi divides the 32 IO pins into 4 groups of 8 pins. Using 24 pins as inputs for status of the 12 turnouts could be interrupt monitored by connecting 2 or 3 interrupt pins from the IO Pi to 2 or 3 Raspberry Pi GPIO pins with voltage dividers to drop from 5vdc on the IO Pi to 3v3dc on the Raspberry Pi.
On the Raspberry Pi 4 (3) currently 24 of the 28 GPIO pins are in use. Three of the remaining pins (0, 1 & 26) are not broken out on the 16-channel PWM HAT leaving one (pin 4) readily available.
- Could move the 4 traffic monitor LED pins from the PWM HAT to the IO Pi freeing GPIO pins to be interrupt driven on the Raspberry Pi. 2-3 voltage dividers would need to be added somewhere.
- On the header board for the Unicorns could bring out the 3 GPIO pins not brought out on the PWM HAT to use as interrupt inputs. There is also room for the 3 needed voltage dividers (6 resistors) and a 3-pin header..