OSTRICKS.DOC OSBORNE 1 UNDOCUMENTED TRICKS
taken from 6/82 Microcomputing letter p. 24.
OZYTRX10.DOC version 1.0
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* *
* original file modified by Bob Schultz *
* of *
* *
* OZYMANDIAS II *
* *
* the *
* *
* Information Interchange Service *
* for *
* Osborne I Computer Owners *
* *
* Box 65 *
* Station G *
* Toronto, Ontario *
* M4M 3E8 *
* *
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BAUD RATE:
The rs-232c baud rate can be set using the
following:
RESET = 057H ;6850 reset
B03 = 056H ;300/600 baud
B12 = 055H ;1200/2400 baud
B96 = 054H ;9600/19200 baud
BASE = 0E500H ;BIOS JUMP TABLE ON MODIFIED
;UNITS, (VER 1.3) ELSE
;0EA00H ON UNMODIFIED.
;(VER 1.2)
MVI C,B96 ;..for 9600
CALL BASE+03CH ;set the new rate
These rates can also be doubled by changing
the jumper J1 in the OS-1. To get to this jumper,
remove the two knobs with an allen key and remove
the screws holding the front panel in place. The
jumper is located behind the RS-232 port about half
way back on the board, just to the left of the 6850.
When the jumper is installed, you get the lower of
each pair of baud rates. When it is removed, you
get the higher.
The bits for the 6850 control register are the
following:
CR1 CR0 Counter Divide Select Bits
0 0 divide by 1
0 1 divide by 16
1 0 divide by 64
CR4 CR3 CR2 Word Select Bits
0 0 0 7 bits + even parity + 2 stop bits
0 0 1 7 bits + odd parity + 2 stop bits
0 1 0 7 bits + even parity + 1 stop bit
0 1 1 7 bits + odd parity + 1 stop bit
1 0 0 8 bits + no parity + 2 stop bits
1 0 1 8 bits + no parity + 1 stop bit
1 1 0 8 bits + even parity + 1 stop bit
1 1 1 8 bits + odd parity + 1 stop bit
CR6 CR5 Transmitter Control Bits
0 0 *RTS = low, xmit interrupt disabled
0 1 *RTS = low, xmit interrupt enabled
1 0 *RTS = high, xmit interrupt disabled
1 1 *RTS = low, xmit interrupt disabled
xmits a break level on the xmit data output.
note: *RTS is a ground true signal. It goes out
without any buffering (ugh!!!) on pin 8 of
the modem connector. Be very careful if you
use this connector. *RTS from the 6850 does
not go to the RS-232 port at all, but does
seem to turn off the data coming out of pin 3
of the RS-232 connector.
CR7 Receive Interrupt Enable Bit
The following interrupts are enabled by this
bit: Reveive Data Register Full, Overrun,
or a low to high transition on the *DCD signal
line (Data Carrier Detect).
note: *DCD has an inverting buffer to pin 4 of both
the RS-232 connector and the modem connector.
BOOTING RIGHT-SIDE DISK DRIVE:
On reset, when you get the prompt for a
carriage return to boot normally, reply with
a double-quote mark "
The right side drive is then A:, and the
left side drive is B:.
This is useful if your left side drive is
temporarily not operating properly (or at all).
PRINTER TOGGLE:
CP/M Control-P is the normal toggle. If addr
0DA0DH is non-zero, the printer will receive an
echo of the console output.
PROGRAM FUNCTION KEYS:
Set them up as in the manual. They are then
invoked with a control 0-9, which is not clear
in the manual.
WORDSTAR BACKSPACE:
After the modification is applied to your
computer, the back-arrow key (which used to be
the delete char key), is now the cursor-left key.
Delete is Control - (minus) (undocumented).
MODIFICATION GOOD NEWS:
1. The capital lock now works for all char.
2. All programs can handle auto-scroll.
MODIFICATION BAD NEWS:
1. In Wordstar, when you auto-scroll, the
display does an annoying left/right dance when
doing a rapid vertical scroll.
2. The upgrade BIOS uses registers X and Y.
CP/M was written in 8080 code where these do
not exist. CP/M programs which use X and Y, and
worked fine previously, may have to be altered
to save X and Y on the stack prior to CP/M calls.
SETUP DUMBNESS:
After running SETUP, you must do a COLD boot
(i.e. hit the reset button) in order to get the
changes into memory. It would be so nice to be
able to get the changes into memory for testing
without writing to the disk, but that's the way
the software bytes.
---------------------------------------------
May 24, 1982 There were some serious pieces of mis-
information in the original file.....57h is a reset
for the 6850. The correct number has been entered
and some information added. I will try to keep this
file up to date and posted on MISSISSAUGA RCP/M
(416)-826-5394. Leave any comments, suggestions,
programs, etc. there or write to me at the address
at the top of the file. Diskettes of programs con-
figured for the Osborne, general purpose utilities,
software tools, tips, problems, some humor and
games, and anything else that I think that people
will like, will be distributed at a cost of $10 per
diskette. Send me any information, programs, etc.
that you like to see entered into the public domain.
ozymandias (the modified Osborne I computer) is up
and down so often with disk problems (Bdos error--
bad sector) that I must have the world's most ex-
pensive yo-yo.
happy yo-yoing {Bob Schultz}
