GPIO pins and stacking another card on top of RaZberry card?

[peteh32]

The other card I would like to stack on top of RaZberry is the Zymbit Zymkey 4i. I was wondering if anyone else has done anything like this, and what your thoughts are?

It seems possible to stack multiple daughter cards on the GPIO pin header, as long as the cards do not conflict in any of the following:

• No conflicts physically - I plan to add a "stacking header" that has longer pins, so you can stack 2 daughter cards

• No conflicts electronically on GPIO pins for UART, I2C, SPI, etc

• No conflicts electronically on GPIO pins for I/O

Based on what I can tell from the RaZberry and the Zymkey, they should not conflict with each other:

• Zymbit Zymkey:
  • Uses GPIO pins 2,3,4 (physical pins 1,3,5)
  • Does not use GPIO pins 14,15 (physical pins 8,10), which are listed as "NC" for not connected
  • Reference: https://community.zymbit.com/t/getting- ... key-4i/202, section on Hardware Installation
  • Note: Below image indicates it does not use GPIO pins 14,15 (physical pins 8,10)

• Z-Way RaZberry:
  • Uses "Serial" (UART), which is GPIO pins 14,15 (physical pins 8,10)
  • Reference: https://z-wave.me/essentials, Chapter 2.1 "RaZberry shield board for Raspberry Pi"
  • RaZberry pinout:
    • Ground
    • VCC (3.3V)
    • "Serial TX", which sounds like UART, GPIO 14
    • "Serial RX", which sounds like UART, GPIO 15

GPIO reference information from https://pinout.xyz



GPIO info on Zymbit Zymkey 4i:

[peteh32]

A little more info I found - here is example from Zymbit on how they suggest using a "pie plate" stacking header. Their Zymkey 4i card is on pins 1-10, and the extra long pins allow stacking a 2nd card on the same pins 1-10: