80C186EC/80C188EC Microprocessor User's Manual

SERIAL COMMUNICATIONS UNIT
$mod186
name
example_slave_1_routine
;**************************************************************;
; slave_1
;
; FUNCTION: This function represents a slave unit connected to a multi-
; processor master/slave network. This slave responds to two
; commands:
; Flash the LEDs on the EVAL Board, and
; Disconnect from the Network.
; Other commands are easily added.
;
; SYNTAX: extern void far slave_1(void);
;
; INPUTS: None
;
; OUTPUTS: None
;
; NOTE: Parameters are passed on the stack as required by high-level
; languages. The slave should be running this code before the
; master calls the slave. Example assumes PCB is in I/O space.
;**************************************************************
;substitute register offsets in place of xxxxh
P1CON equ xxxxh ;Port 1 Control register
P1LTCH equ xxxxh ;Port 1 Latch register
P2CON equ xxxxh ;Port 2 Control register
S1CON equ xxxxh ;Serial Port 1 Control register
S1STS equ xxxxh ;Serial Port 1 Status register
S1TBUF equ xxxxh ;Serial Port 1 Transmit Buffer
S1RBUF equ xxxxh ;Serial Port 1 Receive Buffer
lib_80186
segment public 'code'
assume cs:lib_80186
My_Address equ 01h ;slave 1 network address
TriStateEna equ 08h ;Tri-state buffer enable
TriStateDis equ 00h ;Tri-state buffer disable
FlashLEDs equ 01h ;list of commands unit 1 responds to
Disconnect equ 0fh
public
_slave_1
_slave_1 proc far
push ax ;save registers that will be modified
push bx
push cx
push dx
Example 11-5. Master/Slave — The slave_1 Routine
11-29