What raspi zero pin to use for DTR?

Comments

• Rayman Posts: 16,402

  2026-05-20 12:51

  Or can use RTS instead? That looks to be more easily supported?
• JonnyMac Posts: 9,823

  2026-05-20 13:27

  PST has the ability to toggle DTR and RTS, so this leads me to believe that Propeller loaders probably followed this scheme to allow one or the other.

  Marco's spinc.exe has switches for DTR and RTS.

  
• Rayman Posts: 16,402

  2026-05-21 01:45

  Looks like RTS needs to go through a capacitor before touching reset?
• JonnyMac Posts: 9,823

  2026-05-21 02:12

  I think the usual thing is to have one of those lines control an NPN that has the collector tied to the Propeller RST\ line.
• SaucySoliton Posts: 579

  2026-05-21 04:12

  There was the propeller hat for raspberry pi that did exactly this with the P1. No capacitor. https://github.com/pimoroni/propeller-hat/blob/master/hardware/Propeller-HAT-schematic.pdf

  I thought they used a GPIO for the reset, but I checked my pin chart and GPIO17 can be set to RTS. Some info about configuring the
  Pi serial port here: https://github.com/pimoroni/propeller-hat/blob/master/documentation/Propeller-IDE-Getting-Started.md

  It may work to just put together a script that toggles reset using a GPIO, then runs loadp2.
• Rayman Posts: 16,402

  2026-05-21 08:18

  Thanks @JonnyMac and @SaucySoliton

  Can try both ways and see what works with today’s tools…

  Guess I’m doing the opposite kind of HAT where pi zero sits on top of P1 platform board.

  Actual secret plan is to use K230 board that is in pi zero form factor. That can do really cool AI things. Do want pi zero 2 W to work too though cause cheaper and can do a little basic AI…