ex1a.asm

利用51系列芯片,通过汇编语言编写,实现无线的接收与解码.

;= ex1a.asm ====================================================================
;
; Copyright (C) 2004 Nordic Semiconductor
;
; This file is distributed in the hope that it will be useful, but WITHOUT
; WARRANTY OF ANY KIND.
;
;
; Author(s): Ole Saether
;
; DESCRIPTION:
;
;  nRF9E5 Hello World program. Please note that this program runs the internal
;  8051 on the default power up frequency of 4MHz. See ex3a.asm for an example
;  on how to switch to 16MHz.
;
;  The functionality is the same as in ex1c.c.
;
; ASSEMBLER:
;
;   You need as31.exe to assemble this program. It can be downloaded from this
;   web page: http://www.pjrc.com/tech/8051/
;
; $Revision: 4 $
;
;===============================================================================
           .equ  CKCON, 0x8E
           .equ  P0_DIR, 0x94
           .equ  P0_ALT, 0x95
           .equ  P1_ALT, 0x97

           ljmp  start

start:     acall init

           mov   dptr, #msg
           acall puts
loop:      ajmp  loop

puts:      mov   a, #0
           movc  a, @a+dptr
           jz    puts2
           acall putc
           inc   dptr
           ajmp  puts
puts2:     ret

putc:      jnb   TI, putc
           clr   TI
           mov   SBUF, A
           ret

init:      mov   TH1, #243       ; 4800@4MHz (when T1M=1 and SMOD=1)
           orl   CKCON, #0x10    ; T1M=1 (/4 timer clock)
           mov   PCON, #0x80     ; SMOD=1 (double baud rate)
           mov   SCON, #0x52     ; Serial mode1, enable receiver
           mov   TMOD, #0x20     ; Timer1 8bit auto reload 
           setb  TR1             ; Start timer1
           orl   P0_ALT, #0x06   ; Select alternate function on P01 and P02
           orl   P0_DIR, #0x02   ; Configure P01 (RxD) as input
           ret

msg:       .db   "Hello World!\n", 0