19 lines
1.2 KiB
Markdown
19 lines
1.2 KiB
Markdown
# chibi pc-09
|
|
|
|
|
|
## Description
|
|
|
|
The PC-09 will be a 6309 based microcomputer with a 74LS612 MMU, uPD72020 graphics and keyboard input.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
## Progress
|
|
|
|
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.
|