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Forum Index : Microcontroller and PC projects : The Pico is doomed
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| JohnS Guru  Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
You seem to be thinking a Pico is soldered on the board. It's not. There's a 40-pin socket. So why can't du pont wires be used to map the PicoMite's outputs onto the relevant places? My Pimoroni VGA board arrived, runs Doom, and I now have all 40 pins of the Pico CPU connected via quite long (er, 6"? 9"?) wires (they were all I had) - and it still runs Doom. Next I need to mess around with remapping to suit a PicoMite... going to be hard for me with my lack of knowledge (and I'm out of time for now). I think I can just disconnect a fair few wires to avoid the firmware driving hardware it's not expecting. John Edited 2022-03-19 04:55 by JohnS |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
Do whatever you wish - what you have is a board that doesn't accept a PicoMite *as it was designed*. If you don't use 15 pins for VGA it doesn't let you use them for anything else. You don't *need* a board at all - you can stick a Pico in a breadboard and use Duponts or whatever. You can just solder wires etc directly to the pins of the Pico if you like. It doesn't change the argument. The board is not a good general purpose platform but it's fine if you happen to want 15-pin VGA and I2S audio as that's what it was deigned for. Anything else is a kludge. I doubt very much if Peter will produce a special version of the firmware for that board. I'm quite willing to be proved wrong. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| al18 Senior Member  Joined: 06/07/2019 Location: United StatesPosts: 228 |
FYI there is a current board called the RetroVGA board on Tindie that costs $4.99 (bare board) has 8-bit Color thru VGA, a keyboard, SD card, sound and an Atari joystick port at https://www.tindie.com/products/bobricius/retrovga-raspbery-pico-multi-retro-computer/ The RetroVGA board is compatible with the MCUME retro game emulation software at https://github.com/Jean-MarcHarvengt/MCUME |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Doesn't get me VGA out to an actual monitor without parts I don't have, tools I don't have, etc. Sadly PicoMite VGA as it is, without anyone selling the missing carrier board (or whatever one calls it), is no use to lots of people, which is a pity and inevitably limits its appeal. Hoping to get many more Pico users interested in MMBasic looks tough. It's also a pity that the hardware reference design (thus this Pimoroni board) uses so many pins wastefully. Anyway, this is clearly going nowhere so let's drop it. John |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Thanks. I think the URL should be this Sadly when assembled it's $92.99 John |
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| al18 Senior Member Joined: 06/07/2019 Location: United StatesPosts: 228 |
JohnS thanks for the Tindie link that works. The cost of all the parts on that board including the Pico is about $25. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
I can certainly get you a board for the PicoMite VGA, John. That's no problem. I even have some cases that the board was designed to fit (and should do, but at the moment it's untested as I have no boards). If you can't build it up I can do that for you too. I don't really want to sell these on ebay or whatever. Small quantities are fine, but I'm a hobbyist not a business. Also, it depends on bits being available from ebay sellers and I have no control over that supply. At the moment I have VGA sockets, some level shifters, SD card sockets, power and audio sockets. I'm not sure if I have any RTCs at the moment, but they are easy to get and they just plug in. I have most of the resistors, but perhaps not all the capacitors. With the PCBs I could probably build 4 or even 5 units. Note that, even when fully built with all the options, these boards still have some spare IO pins you can connect to, including the ADC pins. They'll take female Dupont connectors if you want to use them. I've made my design available (so has Peter) so that those who do have the necessary tools and skills can make these - no matter where they are in the world. I can't really do much more as an individual. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
And the cost of all the tools? Learning time? Plus I don't think it's suitable for the PicoMite VGA firmware. I'm fairly sure no pre-built board is and even that the ones that are available are miles away from what's needed. I may well be the only non-hardware person who cares, though! John |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Thanks. Good offer. I definitely don't want to push you (or anyone), especially anyone who's a hobbyist! Weirdly, the PicoDVI design board (by Luke Wren) looks good (DVI over HDMI connector if I've grasped it) except the commercial board(s) have once again not brought out its GPIOs but instead stuck on audio etc chips (like the Pimoroni VGA board has). It's as if the Pimoroni's (sorry to single them out, applies to Pi Hut et al too) don't get GPIO. Olimex have something in design (for a year or so!) that may be OK but it's not out so who knows... John |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
We've seen that before. Manufacturers try to outdo each other in what they can include on their boards - it makes them impressive. They end up leaving virtually no spare pins for the user. Even things like adding a RGB LED eats up pins - and is of no real use in most projects. I regard these as "beginner" boards. They make life easy for experimenting with what's on the board, and if you're happy with that then that's fine. However, those boards are rarely capable of doing anything else. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
This one is better - but it's a kit! I'll buy some screwable (!) parts e.g. DB15 VGA female. I can breadboard resistors. John |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
You can get all sorts of breakout boards (including VGA) that will plug into standard breadboards. You can even get them for nunchuks! The screwable VGA connectors are pretty bulky. I got a pair of crimpers for diong my own Dupont connectors. Very useful. Something I did for VGA was get an old lead (I have all sorts of old computer junk!), cut it in half and put Duponts on so that a monitor can be plugged into a breadboard. If you can, I'd seriously advise you to learn to solder. It doesn't cost much for a basic iron, some solder and some wire cutters and it's a skill that's incredibly useful. You can always upgrade stuff like your iron later. It takes a little practice, but most people can learn to make reasonable soldered joints in as little as a day. I learned using my dad's old 25W Solon iron. I've since found another of the same model, still new and unused in it's original packing. 1960's stuff, I think. It's staying in there. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1642 |
But please get a suitable iron and 1mm diameter or less solder. Get a book like this:  and a sea-of-holes prototyping board and practice with resistors and so on. It's not hard. Bill Keep safe. Live long and prosper. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3378 |
Opinions will vary. My current favorite iron is this one, entirely suitable for my hobby use: "kit" $4.37US, long-lasting replaceable tips, good for many hundreds of solder joints, one to three seconds per joint, can't vouch for the solder (I have 4 of the irons, not bought as kits with solder). Definitely don't use unleaded solder. ~ Edited 2022-03-19 10:50 by lizby PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| al18 Senior Member Joined: 06/07/2019 Location: United StatesPosts: 228 |
I bought one of those soldering irons Liz you mentioned off Amazon for about $11. The only complaint on Amazon was the solder wire is junk - throw it out and use Kester 63/37 Tin/lead solder - type 44 with RMA flux or 331 water soluble flux IF leaded solder is still legal in your country. Leaded solder is NOT ROHS compliant so it's not legal in some parts of the world. |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1642 |
Yes, lead/tin solder 0.6mm is just about right for me. Also use brass wool to clean the tip, a wet sponge gives the tip a thermal shock and can damage the 'tinning' of the tip. Bill Keep safe. Live long and prosper. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
@JohnS Rather than going for the cheapest soldering kit option I'd recommend looking at a true variable temperature iron. Something like this from Amazon. Yes, it costs more, but a temperature controlled iron is so much easier to use for PCB work that you wouldn't believe it. A "known brand" one is still a good price, like this from Bitsbox. It's all about thermal capacity. In an uncontrolled iron the element has to be designed to keep the tip at soldering temp (around 350C) for long enough to make the joint. It's always guesswork. Bulkier tips have greater capacity so keep the solder molten for longer, but they take longer to reheat between joints. Finer tips simply won't solder thick PCB tracks as heat is lost from the tip too quickly. A temperature controlled iron has a temperature sensor close to the tip (usually) and the temperature is maintained very much like a voltage regulator works. More power is fed into the tip as the temperature falls due to heat being conducted away. There are quite a few ways to do this, the most common ones now are to use a little mains voltage controller in the iron itself or a low voltage iron fed from a transformer in a base. I prefer that approach, personally. A third approach is the Magnastat iron, where each tip has its own temperature setting. I'm not sure if they are still around. They were always expensive. The solder you get with a kit is usually a no-name brand and not always very good. It's best to get some decent stuff really. You can still get proper tin/lead solder - my preference - in the UK. Bitsbox sell it. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Thanks everyone. My frustration is that the PicoMite VGA has so much going for it but nearly every Pico/Rpi/etc person will never try it, because so many will not have tools or interest in soldering, let alone be wanting to tackle the pesky task of ordering parts. Instead, they'll stick with any of the "no-soldering" (to abbreviate the above) solutions: Arduino, (Micro)Python, and the many others. Maybe RPi MMB4L is really the answer for such. I've ordered the Amazon iron. I guess my next task is to hunt for appropriate parts? I may as well mention, I've soldered before. Can't say I actually enjoy it. My existing temperature-controlled iron died a few years back and I shrugged and thought Oh well, hardly ever used it. What can I say - I like writing software! Didn't have any trouble using my preferred toolchain to build the PicoMite firmware from scratch & make a couple of changes out of curiosity. John Edited 2022-03-19 21:51 by JohnS |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1642 |
@Mixtel90  I did email WhiteWizzard and suggest that he stock the matherp board and some vital parts but I have had no reply. It doesn't matter to me because I have the boards (still coming) and have the bits needed but it would be good for you Brits and Europeans. It is unfortunate that no-one is selling those boards. Bill Keep safe. Live long and prosper. |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
I gather the matherp board is the one whose Gerbers etc are in this zip How do I order boards please? I gather I send something to somewhere (JLCPCB?)... John |
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