Guru
Joined: 05/10/2019
Location: United KingdomPosts: 8955
| Posted: 09:19am 08 Jul 2025 |
Something that I've been considering for some time. This could be used with anything that can send and receive 3V3 I2C. The board is small enough to get two out of a 100mm square of PCB material.
Any of the Pico pin-compatible devices can be used but a few of the modules, such as the YD-RP2040, are slightly wider and there might be mechanical considerations if the SD card or RTC is fitted.
This can run stand-alone or as a remote IO board. By default it communicates over I2C, but it's easy to use multi-drop COM instead by adding diode D2. Communication pullup resistors are optional.
If I2C is being used for communication:
A mini RTC can be used if required, with an optional additional battery.
A SD card module can be added if required.
Unless the SD card module is fitted all GPIO pins apart from the two allocated to communication (GP16 & GP17)are available to the user.
The power chain is configurable.
5V via USB.
3V3 via the communication supply.
If using this as a master module it can power the communication supply at 3V3.
VSYS is accessible on H5.
There is already some software support for remote IO. Some time ago @lizby produced some routines that might be used with this board. Sorry, I can't find them at the moment.
You could easily connect another SPI device, sharing the port with the SD card and using GP22 as a select line. GP26-GP28 are available on the same connector.