Propeller HAT


#Propeller HAT will get you flying in the world of microcontrollers…

We’ve brought the much adored Parallax Propeller microcontroller to the Raspberry Pi in an experimentation-friendly HAT format that includes a mini breadboard for prototyping and breaks out a whole array of signals from both Pi and Propeller.

Ideal for servo twiddling, robot building, IO-expanding, VGA driving, or rockin’ to classic tunes with sound chip emulators like SIDcog. Parallax’s Object Exchange is packed with code examples and libraries:


  • Stonkin’ 8-Core Micro handles menial IO tasks for your Pi
  • 30 general purpose IO pins controllable by any of the 8 cores
  • Easy to program using the Pi-compatible Propeller IDE and SPIN language
  • On-board 170pt breadboard for hosting your experiments
  • Breaks out Pi SPI, I2C and 15 other pins
  • Fully open-source hardware, right down to the microcontroller!
  • Supplied as a kit with female headers

I’m currently working on documentation for Propeller HAT, aiming to give users an intro to the SPIN language that it speaks in- you can start using and ( hopefully! ) feeding back on this now:

Get yours at


This is a great little demo of a Propeller running a SID sound chip emulator ( really one of my favourite uses so far, even if it’s not particularly imaginative ) alongside a VGA ( or possibly RCA it can do either ) video generator. The sound and text is streamed from a dump file on an SD card.

And a guy on the Parallax forums managed to get the Propeller reading RFID cards with just 4 caps, 4 resistors, a diode and a hand-wound antenna:


Mine arrived today. Looks like a fun bit of kit and I wanted a PWM board anyway which is one of the samples here

Heres the other side


After some fiddling about (and help from @Gadgetoid) I have my Propeller Hat working. I call this project “Scale Lighthouse”, I think its quite an original design. Once I had the resistor and LED where I wanted them the rest of it just fell into place. Not entirely sure I’m harnessing the full power of all 8 cores yet.


Ignore the Trinket in the background, its just there for moral support. Maybe this should be an animated GIF.


New Propeller IDE is now available.

Grab it here, version 0.30.1:

You will also need to do this after install:

sudo chown root:root /usr/bin/propman && sudo chmod 4755 /usr/bin/propman

If you haven’t installed Propeller IDE before you’ll need to follow the instructions for installing Qt5 here:


hum, tempting (especially at a 15% discount)…


do I understand correctly that the propeller only steals the serial from the pi? if so I should be able to daisy chain it to an Explorer using a Black Hat, correct?


More or less, yes, but the Propeller HAT also uses BCM 17 as reset so you’d need to hook that up to something in order to upload new code. Absolutely nothing preventing you from routing it to a spare GPIO pin though ( BCM 7 for example ), and simply running “propman -p 7 yourfile.binary” to upload code.

I’ll get Propeller HAT added to Pinout ASAP- for the purposes of putting it “off Pi” you can totally ignore the HAT EEPROM data, clock and write-protect lines and will only need 5V ( it has an onboard 3.3v regulator ) Ground, TX, RX and your choice of reset pin connected.

Edit Try downloading and installing the software and playing with the IDE before you pick up the Propeller HAT, too. Might help to get familiar with it before diving in!


cool. but you mean pin 8 presumably? either way, I’m taking the plunge!

Edit: where is the fun in that :D


Right, obviously I have a fair bit of soldering to do :D

… but here’s a mockup for your approval.


  • serial in green and yellow
  • ground in black
  • 3.3 and 5V links in red
  • BCM 8 in blue

would this work and provide access to all Propollers functions, as long as I ‘progman’ to pin 8 to upload the code?


oups, sorry, reread your post, 3.3V is superfluous, got it… not sure I am that clear on the reset pin though, should it be BCM8(CS)Explorer<>BCM8(CE0)BlackHat or should I bridge CS to BCM17 on the BlackHat?


You need to be bridging CS to BCM17 on the BlackHAT and thus the Propeller HAT to CE0 on the Explorer HAT. This is looking good though, I might have to try it myself!

Done! And it works, too. At least I have it detecting the Propeller, I haven’t tried uploading anything yet though.

Note- the TX/RX labels on Propeller HAT are reversed so you need to connect TX from the Black HAT to RX on the Explorer HAT Pro, and RX on Black HAT to TX on the Explorer HAT Pro. You should have a total of 5 wires running to the Black HAT- 5v, GND, Reset, RX, TX. These are physical pins 2, 6, 8, 10, and 11.

You can connect a Trinket up at the same time, too, if you use the PWM ( GPIO 18 ) as reset for the Propeller, and CS (GPIO 8) is the reset for Avrdude.


Thanks for the help Phil… good salesman too, the trinket might finds its way to a Lincolnshire home at some point in the future, who knows!


right… I have read all the doc on github, next stop will be the Parallax resources. Can I suggest you envisage doing a tutorial on how to upload code to a headless Pi at some point?

what I mean by that is that, in my case, although it would be possible I don’t really envisage to link up a screen to the Pi that will be hooked up to the Propeller, and plan to program using the IDE on another computer.

I gues the easiest would be to install the full IDE on the Prop-hooked Pi anyhow, transfer the binary and upload it using propman from there but that is a bit overkill (not least due to the QT5 requirement for the IDE). I guess there is a simple solution but right now it seems the Parallax site doc is focused on their old loader so I probably will have to second guess how to proceed.

Of course, best would be to upload via an ssh session, which I guess is on the other hand a bit of a daydream, but it’s worth asking: is it even worth comtemplating and looking into that? Thanks for any pointers (even a RTFM link!)


It’s alive!!!


You can install the full Propeller IDE on your desktop computer- then use propman to upload the compiled binary.

Dan ( of Cambridge Raspberry Jam fame ) was working on Alex’s Raspi Duino recently in order to make a serial connection work over the network- so you could run the Arduino IDE on your local machine but upload to the Pi. I suspect the same thing may be possible for Propeller HAT but I haven’t looked into it!


I read on github that the plan is to extend upload via WIFI, probably some way off though.

You don’t need the full IDE, just compile propman on the machine, though it has a few deps. Well, or copy it over but I’m looking into assembling a doc that can be followed self-contained.


or perhaps I misunderstood your post, yes that is what I did to get going. I’ll try compiling it direct on the prototype Pi though, hopefully that will get rid of those timeout issues I noted elsewhere.


quick note to say: the latest Raspbian Wheezy updates to raspberrypi-bootloader, libraspberrypi, libi2c and python-smbus (available as part of the Raspbian 2015-05-05 image, and pulled from repo at this point in time) left my Propeller fully functional!

Of course that is the whole point, but since I have been holding back till the weekend, I thought I’d post in case anyone was unsure about taking the plunge ;-)

loving the latest IDE btw, extremely polished and uncluttered!