mancuso@psuvax.UUCP (Pat Mancuso) (04/04/84)
This article contains information about the monitor commands and the
character set for the video display.
This is a list of the functions provided by the monitor for the Xerox 820.
They are accessable on powerup from the keyboard.
Command Use
------- -------------------------------------------------------------
Dump Dad1 ad2
Dumps addresses ad1 through ad2. If ad1 is omitted, dumps
0000 through ad2. Output can be held/restarted by hitting
a key. 2 CR's will stop function and return to monitor if
you don't want to see the whole dump.
Memory Mad1
Prints contents of location ad1, and accepts changes. To
change, just type the new value (2 digits), to skip forward
use CR, to skip backward use '-', any other to exit.
Xtest Xad1 ad2
Test for memory errors. Prints a '+' each time a cycle is
completed, 256 cycles for every combination to be tested.
Prints bad addresses if it finds any. Dumb name for command.
Fill Fad1 ad2 val
Fills memory ad1 through ad2 with val. Reads block back to
check for memory errors and reports any if found.
Copy Cad1 ad2 ad3
Copies memory from ad1 through ad2 to memory starting at ad3.
Compares copy with original and reports any differences to
check for memory errors.
Goto Gad1
Does a CALL to ad1. Control can be passed back to the monitor
with a RET instruction.
Read Runit trk sect
Reads a sector from disk and prints it in dump format. If an
error occurs, it lets you know. 'disk error XX Uaa Tbb Scc'
is the error where aa=unit number, bb=track number, cc=sector
number, and XX is the 1771 error code:
bit R/W Seek/Restore/Select
--- ------------ --------------------
7 Drive not ready Drive not ready
6 WR Protected (not used)
5 WR Fault (not used)
4 Not found Seek error
3 CRC error CRC error
2 Lost data Cannot restore
1 (not used) (not used)
0 =1 =0
Boot B (or A)
Loads bootstrap loader from disk and jumps to it. Reads tr0 sec1
into 0080 and then jumps to 0080. Loader cannot use bottom 256
bytes of memory.
Type T
Converts millions(?) of dollars in research into an electric
typewriter. Reads from keyboard and outputs to printer port.
Does not output to CRT.
Input Iport
Inputs byte from specified port and displays it. CR will do the
same for the next port, '-' will do it for the previous port, any
other exits.
Out Oport val
Outputs value to specified port and returns to monitor. Useful for
initializing ports.
-----------------------------------------------------------------------------
CRT information
Control characters
Hex Use
--- ----------------------------------------------------------------------
00-07 None
08 Cursor left
09 Horizontal tab (tab stop every 8 postions)
0A Linefeed
0B Cursor up (wraps back to bottom of screen)
0C Cursor right
0D Carriage return
0E-10 None
11 Clear to end of screen
12-17 None
18 Clear to end of line
19 None
1A Clear Screen
1B Escape
1C-1D None
1E Home cursor
1F Print char between 00 & 1F (special characters)
ESC is used for XY cursor positioning. ESC+'='+rowchar+colchar is the form
where rowchar and colchar is the desired row/col with 32 added to it (20 hex).
The special characters are hidden in the control character section. To print
a special character, prefix it with 1F. To print more than one, prefix each
one with 1F.
The character set is standard ASCII from 20-7F. The character set is repeated
in 80-FF with a blink attribute. If the cursor is on a blank spot, the
standard block cursor will be displayed. If the cursor is on a character, the
blinking version of the character will automatically be displayed.
---
Overall there is a smell of fried onions. (fnord)
:+: Pat Mancuso
:+: Penn State University
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