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Forum Index : Microcontroller and PC projects : PicoMite/PicoMiteVGA V5.07.03 betas - major update
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phil99 Guru  Joined: 11/02/2018 Location: AustraliaPosts: 2514 |
Ok, Thanks Peter. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9547 |
LOL!  In my case, my layout is going to be specific to my needs, and I WON'T be routing out the 40-pin header idea at all. All I want, are the two COM ports, the SD card, the keyboard, and the VGA connector. Somewhat similar to a classic serial terminal device of old, except for the colour VGA and SD card features. COM1 will be level-corrected to RS232, COM2 will be level-corrected to TTL 5v. My PCB will be bigger then both Peter's and Mick's ones as I need to allow for a DB9 connector for the RS232, and I also want to use a full-size SD card. I was not really planning to publish the design as it is going to be custom and specific to what I want to do, but if there is interest, I will publish the gerbers. I will post an image or two later on once I have done the layout, and see if anyone wants the design files. Smoke makes things work. When the smoke gets out, it stops! |
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Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1636 |
I'm interested to know why no-one chose to respond to this question. It is a technique that does work. Connecting a non tri-state device into a tri-state bus via (say) a 1k resistor allows the signals from the tri-state devices to swamp the signal from the non tri-state device effectively taking it out of action while the other device(s) are active. I have used it. Is there a particular reason why it won't work in this situation? I've not used the display and have not seen the circuit but if that won't work could a tri-state buffer be added to the circuit? Bill Keep safe. Live long and prosper. |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7685 |
If you've got one then try it. :) I don't think anyone is going to buy a known faulty display to try to sort it out. Lizby has suggested using a tristate buffer chip, but no-one appears to have tested that approach - or a resistor for that matter. The problem is that the onboard controller doesn't tristate MISO when CS is released. You *may* be able to force things on the SPI bus using resistor coupling, but it's taking it out of spec. Get one bit wrong and nothing will work. 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: 1636 |
Hi Mick, I don't have one and I don't have a Pico. The display seems to be useful and Peter has written a driver for the MM and MM+ see. It has also been used in some Silicon Chip projects (MISO not used). In that link he refers to a 680 ohm resistor in series with the MISO pin. I just thought that if someone does have the display and the Pico they may be adventurous enough to try it. What harm can be done? If it works, good! The magic smoke will not escape. As I said I have used the technique in another project successfully. Bill Keep safe. Live long and prosper. |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2514 |
Perhaps a 4066 bi-lateral switch in place of the series resistor, if that doesn't work. Controlled by CS pin, may need inverting if active low. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3335 |
I don't currently have a Pico and ILI9488 set up, but plan to soon, and I can try a test. What I'm not sure of is that you can test fully with the software as published previously (prior to integration of the PICO source with the VGA code allowing LCD console). You could test to assure that MISO from the ILI9488 is not corrupting SD reads, but since (if I remember correctly), BLIT READ is not available for the ILI9488, you can't test for correct functioning of the ILI9488. (If there's a way, somebody please let me know.) Of course, the source is available and could be modified--but I'm not sure I'm ready to take that deep a dive yet. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1636 |
I think that means that if you remove the MISO pin then BLIT will work. So if a resistor (or and extra tri-state device) can effectively disable the MISO then you can have the best of both worlds? I hope so. One for Peter, I guess. Bill Keep safe. Live long and prosper. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10135 |
http://geoffg.net/Downloads/picomite/PicoMite_Beta.zip PicoMite and PicoMite VGA V5.07.03b4 Minor performance tweaks - gain of c5% |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3335 |
BLIT READ can't work without MISO and (again, if I remember or interpreted correctly), the BLIT READ command is unavailable when the ILI9488 is configured, so I don't know how to test whether all would work if a 1K resistor is added inline on the ILI9488 MISO signal. It's possible to test to confirm that this doesn't result in corruption of SD card reads. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10135 |
BLIT READ works perfectly on the ILI9488 with the latest firmware IFF MISO is connected  Edited 2021-12-30 02:34 by matherp |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3335 |
Yes, and thanks, but if I understand correctly, that's because the SD card and any other SPI devices are on different pins. I think Turbo46 is talking about whether an inline 1K resistor on the ILI9488 MISO pin would allow it to function on the same MISO, MOSI, & CLK pins as the SD card without corruption. That's what I'm not sure can be fully tested with either the new or the older firmware. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| cosmic frog Senior Member  Joined: 09/02/2012 Location: United KingdomPosts: 300 |
Getting this error trying to setup the ILI9488. It doesn't matter which GP Pins I use I always get Invalid Option. Any idea? PicoMiteVGA MMBasic Version 5.07.03b4 Copyright 2011-2021 Geoff Graham Copyright 2016-2021 Peter Mather > option lcdpanel ili9488,landscape,gp10,gp11,gp12 Error : Invalid Option > |
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mobluse Newbie  Joined: 10/02/2013 Location: SwedenPosts: 24 |
Would it be possible to have PicoMite for composite video (NTSC and PAL)? I have some new flat color composite screens for e.g. cars, but also some old thick b/w, for e.g. Apple II. The newer can handle both NTSC and PAL, so if it easier to just support NTSC that would still be useful. Edited 2021-12-30 05:11 by mobluse Maker Pi Pico Rev1.2, DuinoMite-Mini, Raspberry Pi 0-4, iCE40HX8K, Arduino Uno, VM111, STK500, ZX81 |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10135 |
Of course it can. Connect it and see it it works with the SDcard on the System SPI Have you set up the System SPI? Follow the instructions for the ILI9341 in the manual and just substitute ILI9488 |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4020 |
Is OPTION SYSTEM SPI needed first? John Edited 2021-12-30 05:21 by JohnS |
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| cosmic frog Senior Member Joined: 09/02/2012 Location: United KingdomPosts: 300 |
I'm now having trouble getting the SD Card to work. It works fine under Version 5.07.01b7 Thanks. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10135 |
If you are using an ILI9488 and have the MISO pin connected the SDcard can't and won't work, nor will touch. See above |
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| cosmic frog Senior Member Joined: 09/02/2012 Location: United KingdomPosts: 300 |
Just using VGA with OPTION SDCARD GP2,GP3,GP4,GP5. I've just re-read it and I've got the pins the wrong way around.  OPTION SDCARD CSpin, CLKpin, MOSIpin, MISOpin. My fault  Thanks. Edited 2021-12-30 08:32 by cosmic frog |
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| mobluse Newbie Joined: 10/02/2013 Location: SwedenPosts: 24 |
My SD card works on Maker Pi Pico PCB REV1.2 with PicoMiteVGA MMBasic Version 5.07.03b4 and OPTION SDCARD GP15, GP10, GP11, GP12. I can save and load files and the files command works. The function key F1 should type files and Enter, but that doesn't work using PuTTY serial or LXTerminal with Minicom in Raspberry Pi OS Buster. OPTION F9 "files"+chr$(13) works in both PuTTY and LXTerminal. GP15 CSn CD/DAT3 CS GP10 SCK CLK CLK GP11 SDI CMD MOSI GP12 SDO DAT0 MISO The second and third column are according to the documentation for Maker Pi Pico: https://cdn-shop.adafruit.com/product-files/5160/5160_Maker+Pi+Pico+Datasheet.pdf It seems it is not needed to tell GP13 and GP14 to OPTION SDCARD, since SPI bus mode or One-bit SD bus mode is used for SD card access. GP13 x DAT1 GP14 x DAT2 Edited 2021-12-30 11:20 by mobluse Maker Pi Pico Rev1.2, DuinoMite-Mini, Raspberry Pi 0-4, iCE40HX8K, Arduino Uno, VM111, STK500, ZX81 |
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