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Forum Index : Microcontroller and PC projects : PicoMite Pear revisited
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
This one started in one direction and ended somewhere else. :) I was designing another backpack, but this time for the 3/2" ILI9341 parallel LCD display that Peter has used for his high performance game board. It got virtually to the release point then I thought "what if..." and everything went crazy. :) The original PicoMite Pear design used a PicoMite VGA for the display driver. This time it's an ordinary PicoMite but with the parallel LCD display. The control PicoMite has just about everything brought out. Two pins are used for communication between the PicoMites. They can be configured for either a COM port or I2C. Additionally two pins from the Display PicoMite are available. the idea is that these could be used for RTS/CTS or an interrupt system to get a fast data connection. Each PicoMite can have its own microSD card if required. A link is provided to isolate the display Picomite's Reset line so that only the control device gets reset. A single linear regulator powers everything except the display, which is fed at 5V. There's no real reason for other than it makes having a common supply easier than when using the SMPS. Power is from either of the two USB sockets as VSYS is connected in parallel. It might be of interest to anyone who fancies letting one Pico be an intelligent display handler controlled by signals from the controller.  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: 3150 |
Nice. "RTS/CTS" Note that the serial buffering on all the mites pretty much obviates the need for RTS/CTS unless more characters are to be sent than can be fit in the size of the receive buffer. This was tested on the CMM2, where the receive buffer can be multi-megabytes, but with baud rate: 1843200; buffer: 1048576 (open "com2:1843200,1048576" as #1), 1,048,560 characters were sent with no flow control. no RTS/CTS needed Obviously, the PicoMite can't have a receive buffer of over a megabyte, but the circumstances would be quite rare where RTS/CTS would be needed (maybe if you were sending entire FRAMEBUFFERs (but that would not seem to be the purpose of the Pear)). PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
The pins are there in case someone wants them. I just grabbed RTS/CTS out of thin air. :) How/if they are used is up to the individual. I would envisage that the serial link wouldn't normally be carrying a lot of data but it may have to be actioned fast, It may not be sensible to have known message lengths. The pins could well be used for an interrupt system in this case. The size of the receive buffer probably wouldn't be of great consequence unless sending sprites or something. 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: 4243 |
Are the corner screw holes aligned with the mounting holes of the display. So you can make a robust backpack. Volhout PicomiteVGA PETSCII ROBOTS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
They are indeed. That's how it started out. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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