forked from amberisvibin/chibi-pc09
25 lines
1.8 KiB
Markdown
25 lines
1.8 KiB
Markdown
# chibi pc-09
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## Description
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The PC-09 will be a 6309 based microcomputer with a 74LS612 MMU, uPD72020 graphics, PS/2 keyboard and mouse input, and a capable UART.
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The MMU will allow up to 2 megabytes of I/O to be paged into the address space. Pages are 4k. System storage will be paged into the address space as well, as it will be either EEPROM or flash.
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The uPD72020 is a very advanced graphics chip for it's time, capable of accelerated drawing of lines, shapes, fills, and characters. It can be coerced into outputting a VGA signal at 640x480 and *maybe* 800x600.
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Keyboard and mouse will be handled by the VIA VT82C42. It is an Intel 8242 compatible controller capable of both PS/2 keyboard and mouse. It's interface is relatively simple, which makes connection easy. It relies on interrupts, so an interrupt system will be required.
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To avoid the infamous 65C22 bug, the system will use the 16550 UART from the PC ecosystem. It is *relatively* easy to interface this to a 6800 style bus. It has more features than a 65C22 as well. As configured, it will be stable up to 38,400 baud.
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## Progress
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I had started wiring together a board for prototyping, but it was destroyed in hurricane Helene. I am now recreating it in schematic form in order to order a PCB.
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Prototype 1 is currently in progress. It will be a much simpler system. It will have no MMU, just the CPU, some RAM, some ROM, and the UART.
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## License
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This project is licensed under the MIT license. This applies to both the hardware (schematics, bill of materials, pcb layouts) and documentation. This does *not* apply to the datasheets/ directory, the books/ directory or code/assist09/assist09.asm. Those files belong to their respective copyright holders.
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