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Updated information about VT100 factory defaults

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This commit is contained in:
Jeff Parsons 2016-08-21 09:56:44 -07:00
commit 6410ae068c
3 changed files with 113 additions and 73 deletions
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45
modules/pc8080/lib/chipset.js
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@ -501,32 +501,47 @@ ChipSet8080.VT100.INIT = [
0, 0, 0, 0,
[
/*
* The following table contains the data we use to initialize all (100) words of NVR (Non-Volatile RAM).
* According the DEC Technical Manual:
* The following array contains the data we use to initialize all (100) words of NVR (Non-Volatile RAM).
*
* I used to initialize every word to 0x3ff, as if the NVR had been freshly erased, but that causes the
* firmware to (attempt to) beep and then display an error code (2). As the DEC Technical Manual says:
*
* If the NVR fails, the bell sounds several times to inform the operator, and then default settings
* stored in the ROM allow the terminal to work.
*
* However, this behavior may be limited to only certain kinds of "failures", because if I deliberately
* stuff an invalid value in the table, there is indeed an attempt to beep (though sound isn't working yet),
* an error code (2) is displayed in the top-left corner of the screen, but the NVR still appears to contain
* all the same (invalid) data we started with. Perhaps all they meant to say is that the RAM copy of NVR
* settings is reset, not the NVR itself.
* but I think what they meant to say is that default settings are stored in the RAM copy of NVR. So then
* I went into SET-UP, pressed SHIFT-S to save those settings back to NVR, and then used the PC8080 debugger
* "d nvr" command to dump the NVR contents. The results are below.
*
* Using a VT100 configuration with the Debugger attached, use the NVR dumper command ("d nvr") to see how
* other SET-UP changes affect the NVR (after you've saved your changes using SHIFT-S, of course).
* The first dump actually contains only two modifications to the factory defaults: enabling ONLINE instead
* of LOCAL operation, and turning ANSI support ON. The second dump is unmodified (the TRUE factory defaults).
*
* NVR Notes
* ---------
* After enabling smooth scrolling, the word in row 5, col 4 changes from 2E50 to 2ED0, and the final word
* changes from 2E51 to 2E71 (I'm guessing that the final word is an NVR checksum).
* By making selective changes, you can discern where the bits for certain features are stored. For example,
* smooth-scrolling is apparently controlled by bit 7 of the word at offset 0x2B (and is ON by default in
* the factory settings). And it's likely that the word at offset 0x32 (ie, the last word that's not zero)
* is the NVR checksum.
*/
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E00,
0x2E08, 0x2E8E, 0x2E00, 0x2ED0, 0x2E30, 0x2E40, 0x2E20, 0x2E00, 0x2EE0, 0x2EE0,
0x2E71, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x2E08, 0x2E8E, 0x2E00, 0x2ED0, 0x2E70, 0x2E00, 0x2E20, 0x2E00, 0x2EE0, 0x2EE0,
0x2E7D, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000
],
[
/*
* The TRUE factory defaults (not currently used for anything; they're just here for reference, wasting space....)
*/
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80,
0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E80, 0x2E00,
0x2E08, 0x2E8E, 0x2E20, 0x2ED0, 0x2E50, 0x2E00, 0x2E20, 0x2E00, 0x2EE0, 0x2EE0,
0x2E69, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,