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Re: Requirements? [Re: rfka01] #78814 05/06/12 02:14 AM
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Yes, the Z80 is not yet hooked up, at all.

Speaking of which, rfka01: do you have the original document that the "PC100 SYSTEM SPECIFICATION" is scanned from? The PDF has a washed-out stripe down the middle of page 25 which obfuscates some of the details of how the Z80 side works. Is it possible to get that rescanned?

ETA: L_N: the aforementioned page 25 tells (some of) the tale. The default bootup mode is "Z flip", where Z80 0x0000 is 8088 0x8000, and indeed if you boot the driver right now a working Z80 image is stored at 0x8000.

I don't understand how the 8088 holds/resets the Z80 prior to that image being present though. I/O port 0 on both CPUs is a latch and interrupt going to the other CPU, but I don't see anything that would cause a reset. Both IRQ and NMI on the Z80 image at 0x8000 echo whatever they see back through the latch and then HALT.

ETA 2: the latch interrupt is actually RST 30, which thins the plot a little (the code that jumps to appears to copy the RAM around a bit and turn off Z-flip), so that may be all that's necessary to boot the Z80.

Last edited by R. Belmont; 05/06/12 02:28 AM.
Re: Requirements? [Re: rfka01] #78817 05/06/12 08:43 AM
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rfka01 Offline OP
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Hi,

this is the re-scanned page:

Page 25 re-scanned

Robert


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
Re: Requirements? [Re: rfka01] #78820 05/06/12 03:13 PM
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Perfect! Thanks.

Re: Requirements? [Re: rfka01] #78830 05/06/12 09:19 PM
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I got the Rainbow to go a bit further - the Z80 now boots up, copies it's boot image to private RAM, checksums it, and reports the correct checksum back to the 8088. So that gets us past that test, now we fail on error 10, which is "Video VFR" according to the manual. Appears that's the 60 Hz vblank IRQ...

For peeps following along at home, ftp://ftp.update.uu.se/pub/rainbow/doc/rainbow-docs/pc100tm1.pdf is the Technical Manual, which is quite a bit less error-prone and much better written than the System Specification.

Last edited by R. Belmont; 05/06/12 09:22 PM.
Re: Requirements? [Re: rfka01] #78831 05/06/12 09:42 PM
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Ok, got VBL interrupt raise/clear working to its satisfaction.



In order, that's "printer port not working", "restored CMOS defaults" (sounds promising!), and "memory arbitration fault" (not sure what that means).

Re: Requirements? [Re: rfka01] #78837 05/07/12 01:37 AM
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Apparently nobody cares about this thing, but luckily it's interesting enough that I kept going anyway wink



I think it might actually boot once we get the keyboard to respond, but that's pretty much all my time for this weekend.

Re: Requirements? [Re: rfka01] #78839 05/07/12 02:55 AM
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Better Z80 control eliminates both the garbage and the "Z80 Response" error code. Also the keyboard error is different now, I don't know why smile


Re: Requirements? [Re: R. Belmont] #78840 05/07/12 03:23 AM
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Robbbert Offline
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Originally Posted By R. Belmont
Apparently nobody cares about this thing.


No, we are watching good things happen. smile

Re: Requirements? [Re: rfka01] #78844 05/07/12 09:27 AM
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You wrote something about the 8251 core needing interrupts, but the RXRDY and TXRDY pins seem to be implemented.

Re: Requirements? [Re: R. Belmont] #78846 05/07/12 10:04 AM
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ASH Offline
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Originally Posted By R. Belmont
Apparently nobody cares about this thing, but luckily it's interesting enough that I kept going anyway wink


Somebody is always watching wink

Last edited by ASH; 05/07/12 10:05 AM.
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