S/O/S SyMon III --- 6502/65c02 BIOS with monitor and assembler
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For those interested in the vintage 6502/65c02 MPU

Don't worry. You won't need to construct the
monstrosity shown in the photo to run S/O/S
SyMon III. The version presented here has
been modified so that it has minimum
hardware requirements:
NMOS or CMOS 6502 MPU(6502,65c02)
1k RAM
ACIA(6551,65c51) three-wire serial port

This scaled-back system operating software
will fit within a 2764 or similar 8k x 8
read-only memory device, and requires
768 ($300) bytes of RAM. (more, of course,
if you want to run your own applications!)

S/O/S SyMon III has the following features:

Three-wire RS-232 serial device driver
(uses the IRQ interrupt for serial input
and has a 256 ($100) byte input buffer),
2x16 LCD module driver (use is optional),
Monitor with enhanced functions:
assembler, text editor,
Provisions for "copy & paste" method of
program storage/retrieval as well as
transfers between two SyMon systems,
Text or byte-string search functions,
Decimal-to-hex/hex-to-decimal conversion,
ASCII-to-hex/hex-to-ASCII conversion.

S/O/S monster main board

above: S/O/S system with (almost) everything...
It has the following:
CMOS 6502 MPU running at 1.77778 MHz:
16k system program ROM:
40k total system RAM:
-Toshiba(TC5564PL-15), NEC(D43256C-12L)
Lowest 8k RAM is non-volatile
Battery backed real-time clock:
-Dallas Semiconductor(DS1216)
RS-232 serial port:
Parallel (Centronics) printer port:
Programmable priority 8 Ch. interrupt controller:
-Advanced Micro Devices(AM9519ADC)
640k double-sided floppy disk drive:
Full ASCII keyboard:
TTL monochrome 80x20 CRT video display
using 16 MHz dot clock with individuallly
controllable two-level character brightness:
8k custom video character generator ROM
with four font styles:
-Texas Instruments(TMS2764-25JL)
32k video display buffer RAM:
32k video display ROM (user's guide text):
-Advanced Micro Devices(AM27C256-90DC)
Console mounted video scrolling control
(allows scrolling up to 8 full screens)
Programmable sound generator:
-General Instruments(AY-3-8910)
Text-to-speech processor pair (with 2k buffer):
-General Instruments(CTS256A-AL2)
-General Instruments(SPO256A-AL2)
Buffered address/data/control busses for
external I/O hardware
Memory and I/O DMA capability

Content copyright (c)2007 Brian M. Phelps
Files may be distributed freely provided they have not been modified in any way.

Not liable for any damages nor losses due to the download or use of any content within these pages.