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Forum Index : Microcontroller and PC projects : PicoMiteHDMIBTH query

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Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 9260
Posted: 08:52am 27 Oct 2026
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I assume this firmware is compatible with the OPTION CYW43 PINS system? I'm designing a new board that is based on bluetooth as it's main system but has the option of using Pico 2 + RM2, Pico 2W or Pimoroni Pico Plus 2 W. Obviously the Pico 2 (or clones) don't have the standard pins for a wi-fi module.
Mick

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Mixtel90

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Posted: 10:43am 27 Oct 2026
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COMPETITION

I couldn't think of a snappy name for this board so I'm open to suggestions!

Get your suggestions in before Friday 09:00 AM GMT. The winner gets to see their suggestion on the PCB and a free unpopulated board posted to them. Postage will be by international standard first class post.

Board details

Same size as Elemento but different fixing centres
Interesting power button circuit using mosfets
Virtually all SMD soldering (1206), including the HDMI connector (sorry, not much through-hole)
Will accept modules as listed in original post
module's USB connector accessible from front
I2S audio
mini RTC, with space for CR2032 holder
micro SD card
CP2102 module for USB-C and console connection
headphone socket on front (fed from I2S via resistors)
no space for GPIO as such, but GP28 on a pin and two QWIIC sockets, one on each I2C.

You will have a choice of either waiting until I have a prototype doing something or taking a risk. :)
Mick

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Volhout

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Joined: 05/03/2018
Location: Netherlands
Posts: 6204
Posted: 12:03pm 27 Oct 2026
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Mick,

When you are using BT for everything (mouse, keyboard, sound), why is there a USB-C console through CP2102 ? You can use the Pico CDC port. That will make a very simple design. HDMI, BT, no I2S sound, no CP2102, no USB hub, only SD card.

But BT eats some RAM, so it may be a good idea to base it on a module that also has PSRAM. And yes, you can still have some IO pins on headers.

Call it FUTURA (no more PS2/USB devices, all BT or BTLE). Would be a good device for living room (playing games on the couch) with BT keyb/mouse. Better even when sound would be on HDMI.

Volhout
Edited 2026-10-27 22:10 by Volhout
PicomiteVGA PETSCII ROBOTS
 
Mixtel90

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Posts: 9260
Posted: 12:31pm 27 Oct 2026
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This particular board isn't designed like that. I agree that a truly minimalist system can be built, but this isn't it. :)

This is specifically designed for the HDMIUSB firmware, running on any of the 40-pin Pico 2 family. This starts up after installation using the USB port in Host mode (I assume!) so  you will need the serial console to set HDMI PINS and CYW43 PINS. They can't follow the standards for the RP2350B chip - not enough pins.

You can get PSRAM by using the Pimoroni (or Waveshare?) module (when it's in stock) but otherwise you can't have it on a (unhacked) 40-pin module.

Oh, if you use a processor module that is flat on the bottom (like the Pico 2) you can surface mount it.
.
Edited 2026-10-27 22:35 by Mixtel90
Mick

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matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 12083
Posted: 12:37pm 27 Oct 2026
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Don't understand what you are trying to achieve with this one. Your modular PC3 does everything and can run pretty much any of the firmware variants
 
Mixtel90

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Posted: 01:12pm 27 Oct 2026
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It started with trying to get something like the PC3 into the Elemento case. I have these crazy ideas sometimes. :)  Elemento lets you use different 40-pin modules. One of its failings is the height of the RTC module. So, basically, I've stripped out the USB system and VGA, added the facility to use any 40-pin processor with a HSTX and optimised for surface mount in most cases.

Just waiting for my PC3x Version 2 boards so I was killing time. :)
Mick

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vegipete

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Joined: 29/01/2013
Location: Canada
Posts: 1186
Posted: 07:56pm 27 Oct 2026
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Elementwo - it's version 2, so to speak?
Or, Elemen2.
Visit Vegipete's *Mite Library for cool programs.
 
homa

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Joined: 05/11/2021
Location: Germany
Posts: 734
Posted: 09:58pm 27 Oct 2026
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Bluebell - Blue(tooth) as the main system, bell for the I2S sound. And a very British flower. :)

Alternative: Elementino - the little brother of Elemento.

Matthias
 
Mixtel90

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Posts: 9260
Posted: 09:58am 28 Oct 2026
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Now we know what it will almost certainly look like:



The fixing centres are the same as Elemento vertically but they are wider horizontally due to lack of PCB space. It might not be possible to get it into the original Elemento case due to projections front and rear, but it would fit the 3D printed version nicely, subject to the panels being modified (and me finally sorting the case out!).
Mick

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Volhout

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Location: Netherlands
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Posted: 10:51am 28 Oct 2026
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Hi Mick,

So essentially this is a PC3 with the USB hub circuit external (standard 4 port hub with USB-C or microUSB connector connecting to the pico2 USB connector) and virtually no GPIO pins free (2350A).

And there is one SOT23 FET on the bottom side (VSYS ?)

Volhout
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Mixtel90

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Location: United Kingdom
Posts: 9260
Posted: 01:08pm 28 Oct 2026
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Nope, this isn't a PC3. It's incompatible. To get compatibility you need a suitable RTC, GP27 and GP32 available as well as PSRAM. Obviously those pins aren't available on a 40-pin module. For a PC3=compatible modular build I did the PC3x, which gets as close as I can get.

This board is a little different and is more like Elemento. You can plug in (or solder in) any 40-pin RP2350-based module. Unlike Elemento you are stuck with HDMI for video though. It is specifically designed for the PicoMiteHDMIBTH firmware and is intended to use Bluetooth for keyboard, mouse etc. I2S is available if you prefer it to bluetooth audio (I think the audio quality is better).

USB is available if you want it. What looks like a SMD under the board is a solder blob link. If the board is powered via VSYS (the default to prevent a back-feed) then the USB socket is not powered. Swap the link over to power via VBUS to make the USB socket powered.

If you can get a Pimoroni Pico Plus 2 W or clone thereof then you can leave off the RM2, gain more flash and get PSRAM. It has to be plugged in.

A Pico 2W can be plugged in and the RM2 not used.

A Pico 2 can be soldered directly to the board and used with a RM2.
Mick

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mozzie
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Joined: 15/06/2020
Location: Australia
Posts: 475
Posted: 01:52pm 28 Oct 2026
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G'day Mick,
I like following this and your other designs using modules, the fact we can mostly assemble them ourselves and replace a module when the "magic smoke" escapes is a great advantage.

Just checked and the PicoMiteBTH firmware supports the VGA222 drivers, whilst I don't have an adapter to actually see how it looks yet, this would allow VGA and Bluetooth to work on this design using the same 8 pins as the HDMI.

Just a thought.

Regards, Lyle.
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 9260
Posted: 02:25pm 28 Oct 2026
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Electrically yes. The HDMI output uses the same pins and resistor values as the Pico Computer 3 so the same adapter should work. Whether you can get the USB-C power plug in alongside it is something that I can't answer. :) A short HDMI M-F lead would fix that though.
Mick

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