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Forum Index : Microcontroller and PC projects : PicoMite: PicoGAME VGA development
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
LOL! :) I know what you mean. They are actually intended as additional packing to reduce damage to equipment. In this case the notes help keep the electrons in nice neat lines so that the pictures are the right way round. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4262 |
There is a whole WIKI page dedicated to the fact that no-one reads the manual RTFM PicomiteVGA PETSCII ROBOTS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
I hadn't read that. Of course. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
I just spent about 2 hours assembling a V1.4A board. Here are a few notes: The configuration pads for 3V3EN on the bottom of the board are not connected to ground. The "far" side of the configuration pads should be grounded. The pads for the SMD audio jack have the Ground and Right channel reversed. I was able to remove my jack and cut some PCB traces, then add some #30 "rework" wire to get it connected properly. The spacing of the resistor pads is a bit tight for 1/4 Watt resistors, you will need to bend the leads sharply as close to the resistor body as possible. I haven't tested the joystick ports yet. Is there a test program available to check the joystick functions? Seems like it should be fairly simple, but I haven't deciphered all the modes and functions yet. Edited 2022-05-19 01:49 by Sasquatch -Carl |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
Thanks Carl. All points noted - I needed *something* to fix for 1.5. :) The audio jack is a pain, but I was looking at changing the audio side anyway. I didn't notice when I was testing as I'm partially deaf. The resistor leads are a little tight, but I had no problem with the MF ones I have. CF sometimes have slightly longer bodies and can be difficult. TBH I used a standard arrangement in Sprint Layout 6 and the next one up was way too big to be useful. I'll consider making a new one now I know how to. :) I posted a general test routine just the other day. https://www.thebackshed.com/forum/ViewTopic.php?TID=14670&P=16#186470 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4047 |
Specifically what are we talking about and do I need to do anything about it on my v1.4 board ? Or if due to not paying attention when ordering, the only 2R2 resistors you have are 0.5W; it is fortuitous that there's a bit of extra space around R9. Best wishes, Tom Edited 2022-05-19 04:13 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
It was the 2R2 that I had with a slightly longer body too. :) Yep, it might be advisable to connect 3EN to GND with a wire link (or a blob of solder to the GND next to it). The SMPS is running while the linear reg is on. It probably won't cause a problem, but it would be a good thing to do. For the next issue: I've fixed the 3EN link pad. I've fixed the 3.5mm jack socket issue. I'm not going to change the resistor centres - I think it would be a major hassle on this board. I'm going to make another resistor block, allowing another 1.27mm. I work on a grid that size, with the ability to go to half that for quick and easy fine positioning (although I can use other grids, I have to work on 0.1" as a base). There's no particularly easy way to patch round the 3.5mm jack socket, I'm afraid. I've done it on the next version of the PCB. In the meantime I recommend not using the SMD socket. EDIT: For anyone who has built this with the SMD socket, it's possible to remove it using solder wick to draw the solder away from the joint. I also slid a scalpel in underneath to lift the socket from the board. There are two tiny ground connections to the pad marked 1G which have to be cut and a trace coming from the hole marked 2R. After the links are cut and the socket refitted you need to link the 1G pad to the 2R hole and the pad that went to 2R to GND. It's fiddly, but it can be done. Edited 2022-05-19 05:18 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
Thanks for the test program Mick. Somehow I missed that post in the thread. I can now report a successful build of V1.4A! By happy coincidence my NES controllers arrived today on the slow boat "AliExpress" Overall, I am very pleased with the design. I like the options for the SD socket, Audio Jack and Keyboard voltage translator. I was able to build the board with parts that I already had on hand. I also appreciate the configuration links on the bottom side of the board. There is a lot of flexibility in this design to configure with different options. As for the SMD audio jack, it's a fairly easy fix once I figured out what the problem was. Even easier if known ahead of time when building. Thanks to all who have contributed to the project! -Carl |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
That's probably the first 1.4A in existence. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
Probably (hopefully!) the last word on this aspect. :) When I started using the PSG03613 3.5mm jack socket for audio I was unable to find any documentation on it - no pinouts or anything. Eventually I figured out what seemed to work and built the prototype using it. Of course, I had all sorts of problems in getting the channels the right way round. I was pretty meticulous when laying out the 1.4 board in "getting it right this time", particularly as I was incorporating the SMD part, which I had info for. After Carl's problem with the SMD socket (which I'd also fitted) I took it off and fitted the through-hole socket that I'd recycled from the prototype. The channels were wrong way round... Hang on, I have info for the SMD, one channel is correct, so the through hole must be wrong... It appears that the two sockets are reversed. The through hole has Left closest to the edge of the pcb and the SMD has Right. Consequently, for versions 1.4 and 1.4A if you are using the through hole socket then the channels are reversed. Either reverse your connections/headphones/speakers/ears or fit crossed-over links on LB2 or cut the tracks to GP6 and GP7 and link them, crossed over, to R1 and R4. For the SMD socket the mods are as in yesterday's post. You'll be pleased to know that I've now corrected *both* blocks on Sprint Layout. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3155 |
I hope this isn't altogether OT: I have a 7" HDMI display which has an input labeled "VGA". It's the shape of a USB "mini" connector, and looks like it accepts a 5-pin plug.  If the display came with a cable for that, I've lost it. Does anyone know of such a cable and what it would be called and where available? If this display would work, it might actually get me to build a Picomite VGA board. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
As far as I know there has never been a standard for a mini version of VGA. Anything other than the normal 3-row D connector is manufacturer specific. You may have fun with this one. However, the USB-A connector is intended to power one of the little VGA to HDMI converters so you don't really have a good excuse not to build one. ;) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2142 |
You could improvise your own connector. The first step is to work out which pin does what. First search the web to see if anyone else knows. Then plug 5 DuPont wires in. The shroud must be ground and the 3 colour pins should measure 75R to ground. The remaining 2 must V & H sync. You will have to sort them out by trial and error. Put a PicoMite on a breadboard and plug the DuPont wires and earth into its VGA outputs via 220R for red and blue and 330R and 680R for green high and low. it doesn't matter which colour is which at this stage. Type CLS RGB(White) and see if it works, if not swap the sync. wires an try again. If that works you can then sort out the colours. If you can't purchase a plug anywhere it is possible to make a crude one. find some thin, stiff wire such as a small paperclip or magazine staples and solder them at the end of a piece of strip board then bend to fit the holes. Make it rigid with a little 5 min. epoxy. For the earth cut a small rectangle of tin plate from a can lid. Solder a wire on and epoxy it on to the plug (which you have insulated with epoxy) and bend and trim it to fit into the socket shell. Just one side should do, too hard to make it go all the way around. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
It's annoying because in most respects it's a standard USB connector. The problem is that USB leads only have 4 wires - pin 4 is used for OTG detection and has no connection at one end and is grounded at the other. (Yep, I've been looking it up!) You can get 5-wire mini USB cables, but they are a bit thin on the ground. They don't seem to be sold as VGA cables though, so bear that in mind. Probably not much use to you, but I found what seems to be one on Amazon.uk. Edited 2022-05-20 17:48 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2142 |
Assuming it is Mini USB here is a plug with 5 pins. https://www.aliexpress.com/item/1005001908243531.html |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
Hey, those are good! :) I don't think they will fit though. They seem to be 5+5 pins, not just 5 in a row. The shell looks like it's the same as mini USB. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2142 |
Looked in the end of a Mini USB plug with a magnifying glass. There are NO pins. Same as regular USB, just mini. So that plug is something else entirely. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
By Gad, Sir, I do believe you're right! A mini USB has 5 flat pads, the two outer ones longer than the middle ones, all on the long side. Back to square one - that's a special connector. :( From the apparent scale I suspect Dupont connectors will be too big to fit. Edited 2022-05-20 19:30 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4047 |
Is this the aberration in question: https://www.aliexpress.com/item/32830643122.html Unfortunately the photos don't show what is in the "USB" enclosure, but presumably it's not USB because surely you can't just wire USB <-> VGA. Best wishes, Tom Edited 2022-05-20 19:39 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6825 |
It's what I would imagine it to look like, Tom. As you say, it can't be USB as USB doesn't carry video - even if it looks like it. Pity they didn't show the inside of the mini plug. At that price it's probably worth a try. I tried zooming in on the largest pic and it looks as if there are pins in there. Edited 2022-05-20 20:00 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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