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"Timothy J. Massey" wrote:
I am absolutely brand new to the list, and I'm trying to figure out what's going on. The project sounds very exciting!
I'm curious, though: A PCB? What for?
Ah, since there's no web page describing it yet (when it's done one will be put up, hopefully next week) I'll explain it briefly.
It performs three functions:
POST - For debugging purposes, it will display POST codes from port 80. However, there will be a header for a character LCD module to display human readable bootup messages on a different port. It can also be used by the operating system to display statistical information (ala LCDProc for Linux), useful for servers, etc which have no monitors.
Flash switch - Will switch between a backup flash and a test flash so that you won't need to burn code using a ROM programmer and physically insert them into the motherboard (or risk blindly programming one BIOS). You switch between them using a switch on front of the PC (in a 5-1/4 slot, next to the LCD if you have one, I'm sure everyone has empty ones). The backup BIOS is wired so that it cannot be written to (this has the useful side effect of making your PC immune to flash virii). This allows for a really quick development cycle (yay!) and anyone seriously working on OpenBIOS will really benefit from this.
GPIO - General purpose I/O. This is for the hardware people (like me) who have run out of parallel ports and want to make your PC control neat stuff. This also makes it great for the embedded people (like me) who want to make systems without requiring unnecessary hardware (video card). You can even use the test flash for your "target" system and the backup flash for your "development" system. This can control relays, A/D, D/A, etc, important if you do the kind of stuff I've been doing (industrial process control, I hate PLCs). It's great for students learning hardware programming as well.
I'll try to finish it up this weekend, one thing I'm wondering about though. How fast does the processor try to read the BIOS? We may be able to get away with putting most of the flash lines on the ISA bus, only needing one wire into the socket. Will this work? I'll make a board and try it out anyway unless someone tells me otherwise.
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