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XT-IDE Rev 2 UART Location

hargle said:
grrr. lost my previous attempt at this.
ok, I cannot see your screenshot- my workplace blocks lots of photo hosting sites.
anyway, we can step through this with an example.

c:\>debug
-d 40:10
0040:0010 27 42 00 77 02 00 00 20-00 00 32 00 32 00 34 05 'B.w... ..2.2.4.
...

The 27 42 are the 2 bytes we're targeting, and since we're only concerned with bits 11:9, we really only need that "42" since that value has all the bits 15:8.

42 in hex breaks down to 0100 0010 in binary. (you can do this in google!)
------------------------------^^-bits 11:9 are 001
Add 1 to that value. New value is 010.
roll it back in 0100 0100 = 44

you want change "42" to "44" in debug:
-e 40:11
0040:0011 42.
---------------^^
you will type 44 here and then enter
done.
-q

this change, combined with the earlier one that sets the base address for your 2nd com port, should now have tricked the BIOS/software into seeing 2 COM ports.
Click to expand...

Thanks, I did this, and now syschk no longer says (BIOS sees only 1). However, Bananacom and Checkit3 still only see 1 COM port.

Probably a lost cause for bananacom. :/ But we did trick the BIOS into seeing it.
 
How about this:
Instead of adding COM2 at 2f0, how about replacing the 3f8 address stored in 40:0 with 2f0? In other words, we're replacing the existing COM port and pointing to the XTIDE uart. this would effectively kill off the port you have already, but it's just an experiment. Then tell banananaramacom to use COM1.


I can't think of any other things that would need to be updated to get BIOS/software to be able to detect another UART. Unless the high speed oscillator itself is causing software to not be able to figure out how to talk to it. (I dunno)
 
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