QWIIC 1 + 2, expansion

[andypiper]

Per the conversation here, QWIIC2 on the right side can handle a Wii Nunchuck as a Kempston joystick.

Is QWIIC1 set up for anything specific.
(can you tell I have not done any proper digging in the firmware code yet... PlatformIO can wait for later in the week!)

I guess the idea of the expansion header is that it is straightforward to solder on a header and play with the GPIO... I wonder how that could be interfaced with Speccy BASIC... 🤔

[andypiper]

I have managed to get a Pimoroni Qw/ST controller working on Qwiic2 in place of a Nunchuk, emulating the Kempston! I will tidy this up and share some forked code shortly.

https://makertube.net/w/gyLyf5CoK4kzkoMaY5w6Co

I've also managed to get the Pimoroni multisensor working, and detected in BASIC in the 48K.

Having some issues with Qwiic1 though, it does not seem to want to play.

[cgreening]

Hmm, I can't see anything in the code that would stop QWIIK1 from working. Let me double check the pins are correct!

[andypiper]

It is exceptionally likely that I am doing something wrong, too... I was more interested in tinkering with I2C input. I should probably revert to the shipped firmware and check, before complaining 🙂

[cgreening]

It's entirely possible there is an error somehwere on my side. Much of my testing was on QWIIC2

[andypiper]

OK. Disclaimer, I am not a Kicad expert!

Based on what I think I see (?) in the schematic and in the firmware code:

• Qwiic1 connects to GPIO 5/6 but is not referenced in the firmware
• Qwiic2 connects to TX/RX == GPIO 43/44 which is referenced as for Nunchuk or Adafruit Seesaw in the firmware.

Is that correct or am I misunderstanding something?

[cgreening]

Yep - that’s correct. At the moment qwiic1 is not used by the firmware. We could set things up so we try and detect the nunchuck (or any other peripherals) on either qwiic1 or qwiic2.

…

On Thu, 17 Jul 2025 at 22:15, Andy Piper ***@***.***> wrote: OK. Disclaimer, I am not a Kicad expert! Based on what I think I see (?) in the schematic and in the firmware code: - Qwiic1 connects to GPIO 5/6 but is not referenced in the firmware - Qwiic2 connects to TX/RX == GPIO 43/44 which is referenced as for Nunchuk or Adafruit Seesaw in the firmware. Is that correct or am I misunderstanding something? — Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFMTAGLHXLAVFDMDJVXYQL3JAHA5AVCNFSM6AAAAACBROFOSCVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGNZZHAYDKMI> . You are receiving this because you commented.Message ID: ***@***.*** com>

[andypiper]

Ok, thanks for the verification. I have some learning to do here as I dive into Platform IO etc. My current idea is to have the firmware check for connected I2C devices or nunchuck on either connector. Will give that a go!

[twigsdw]

Could you use this for a DE9 connector and joystick support?

[andypiper]

I don't see why not. That said, I do not own a joystick with DE9.

I can see that there are DE9 adapter boards, so in principle that would need wiring to a QWIIC connector and the corresponding I2C code written and added to the firmware. There's an Adafruit adapter for PC joysticks (DE15).

I've got a fork locally that works with either the Adafruit I2C joystick or a Pimoroni QwSt board. I'm thinking about how best to add this and contribute it to the main project without breaking existing support for a Wii Nunchuk.

[cgreening]

It would be nice if we could make the code "autodetect" the controller that's connected. I think this should be possible with I2C.

[n4ppy]

Just to note, i got some jst connectors from Ali but the wires are "wrong" green/yellow are power and black/red are i2c. So if you get something double check what's what.
Works great and via IN 31 available in BASIC
Up: Bit 3 (decimal value 8) is set.
Down: Bit 2 (decimal value 4) is set.
Left: Bit 1 (decimal value 2) is set.
Right: Bit 0 (decimal value 1) is set.
Fire: Bit 4 (decimal value 16) is set.