Dec 062017
 
Excom is a BIOS int 14h COM port handler that provides interrupt-driven buffered input. Includes ASM source code.
File EXCOM.ZIP from The Programmer’s Corner in
Category Assembly Language
Excom is a BIOS int 14h COM port handler that provides interrupt-driven buffered input. Includes ASM source code.
File Name File Size Zip Size Zip Type
EXCOM.ASM 32467 5181 deflated
EXCOM.DOC 1707 627 deflated
EXMODE.C 7122 1744 deflated
TPCREAD.ME 199 165 deflated

Download File EXCOM.ZIP Here

Contents of the EXCOM.DOC file


EXCOM mini docx

Dr. Dobb's Journal, June 1987 - Extended COM Port Driver

Buffered input - no lost data
input flow control - XON/XOFF or control lines
output flow control - control lines
works with existing software
removal - without reboot
19,200 and 38,400 baud operation
type ahead with CRT's
upward compatible

Excom is functionally equivalent to the BIOS int 14h COM port
handler with three significant enhancements:

1. it provides interrupt-driven buffered input
2. it has an extended set of configuration parameters
3. it has flow control selection and higher baud rates.

Excom is made up of three major sections, the COM port data
input interrupt handler, the replacement for the BIOS int14h handler,
and the code to install and initialize Excom.


Installing Excom:
Install EXCOM early in the boot process - BEFORE a PRINT/D
Using EXMODE to install

De-Installing Excom:
the book says use EXMODE to remove


BUGS:
1. Control-S (^S) and Control-Q (^Q) are sent without any regart
to the UART being ready or the control lines being correct.



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