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Forum Index : Microcontroller and PC projects : Basic on a Xiao 2040
| Author | Message | ||||
| pwillard Guru  Joined: 07/06/2022 Location: United StatesPosts: 324 |
 It just seems hilarious to me that I can emulate a retro boot-to-basic computer with a Seeed Xiao 2040 postage-stamp-sized device. Edited 2022-06-11 22:17 by pwillard |
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hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 735 |
 Me Too ! my site |
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led-bloon Senior Member  Joined: 21/12/2014 Location: AustraliaPosts: 208 |
Me three!  led Miss you George |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3481 |
That's mighty compact. Can you share a circuit diagram? Have you altered the MMBasic source? Great job anyway. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| led-bloon Senior Member Joined: 21/12/2014 Location: AustraliaPosts: 208 |
The PicoMiteVGA software has been modified to match the XIAO GPIO pins. As there was one pin short to add a PS2 mouse, I joined hSync & vSync to form cSync in the software, freeing up the needed pin. This works fine on my 16yo LCD TV and also on my 1yo Philips monitor. (however it may not work on ALL [early] monitors) Device | Pin || Pin | XIAO | Pin || Pin | Device ----------------------------------------------------------------- SDcard 5 || 1 GP26 5V0 14 || 2 || 2 GP27 Gnd 13 || 3,3 SDcard,PS2 7 || 3 GP28 3V3 12 || 4,4 SDcard,PS2 1 || 4 GP29 GP3 11 || Green2 VGA PS2 Clk 5 || 5 GP6 GP4 10 || Red VGA Data 1 || 6 GP7 GP2 9 || Green1 VGA VGA cSync || 7 GP0 GP1 8 || Blue VGA VGA: Single O/P colour (Red & Blue) 330 Ohms Dual O/P colour (Green) 390 & 1K Ohms cSync fed into the hSync I/P of the VGA connector SD Card: Using simple uSD card adapter with 3V3 supply __________________ / 1 2 3 4 5 6 7 8 | / 9 | | | NB Before setting Option SDcard, GP29 MUST be set to "OFF" (done once only) OPTION SDCARD GP29,GP26,GP27,GP28 PS2 Keyboard: My eMachine Keyboard uses 3V3 supply ok 1 - Data 3 - Ground 4 - VCC (3V3) 5 - Clock Miss you George |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3481 |
Thanks for that. That's PCB worthy. Nice work. No sound and no controller, but heck of a job to provide so much with so little. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2832 |
The composite sync is very clever. For monitors that don't support composite sync a simple R-C sync-separator could recover the vertical sync. For really obstinate ones an additional C-R would remove the V from the H. Could be useful to gain a pin on the regular PicoMiteVGA if Peter likes the idea. |
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| led-bloon Senior Member Joined: 21/12/2014 Location: AustraliaPosts: 208 |
The cSync idea was not well received but I, personally, am not looking at supporting any other software/hardware publicly. However I am working on the Waveshare RP2040-Zero now, which has 9 extra GPIO (just not Vero strip board friendly for GP09-13). Definitely a better device to consider (and cheaper!) Just great fun, I wouldn't be dead for quids! Big, BIG, thanks to Geoff & Peter led Miss you George |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3481 |
That's the ticket. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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