ex2a-rx433.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.

;= ex2a-rx433.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:
;
;   This example should be used together with ex2a-tx433.asm. One nRF9E5
;   evaluation board (receiver) should be programmed with the hex-file generated
;   from assembling this file and the other evaluation board (transmitter)
;   programmed with the hex-file generated from assembling ex2a-tx433.asm.
;
;   All switches on the DIP-swith S206 on the receiver must be set to the "on"
;   position and all switches on the DIP-swith S205 on the transmitter must be
;   set to the "on" position.
;
;   When one of the switched SW1-SW4 on the transmitter is pressed the
;   corresponding LED on the receiver is turned on.
;
;   The functionality is the same as in ex2c-rx.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: 2 $
;
;===============================================================================
           .equ  EXIF, 0x91
           .equ  P0_DIR, 0x94
           .equ  P0_ALT, 0x95
           .equ  P1_ALT, 0x97
           .equ  SPI_DATA, 0xb2
           .equ  SPI_CTRL, 0xb3
           .equ  SPICLK, 0xb4

           ljmp  start

start:     acall init
           clr   P2.4            ; TXEN = 0
rxpacket:  setb  P2.5            ; TRX_CE = 1
waitdr:    jnb   P2.5, waitdr    ; Wait for DR = 1
           clr   P2.3            ; RACSN = 0
           mov   a, #0x24        ; R_RX_PAYLOAD
           acall spi_wr
           mov   a, #0
           acall spi_rd
           setb  P2.3            ; RACSN = 1
           clr   P2.5            ; TRX_CE = 0
           clr   c
           rrc   a
           mov   P0, a
           ajmp  rxpacket

init:      mov   P0_ALT, #0x00
           mov   P0_DIR, #0x00
           mov   SPICLK, #0x00
           mov   SPI_CTRL, #0x02
           clr   P2.3            ; RACSN = 0
           mov   a, #0x03        ; Config address 3 (Rx payload)
           acall spi_wr
           mov   a, #0x01        ; One byte Rx payload
           acall spi_wr
           mov   a, #0x01        ; One byte Tx payload
           acall spi_wr
           setb  P2.3            ; RACSN = 1
           ret

delay400:  mov   r7, #130
delay401:  djnz  r7, delay401
           ret

spi_rd:
spi_wr:    anl   EXIF, #0xdf     ; Clear SPI interrupt
           mov   SPI_DATA, a     ; Move byte to send into SPI_DATA
spi_rdwr1: mov   a, EXIF         ; Wait until...
           jnb   acc.5, spi_rdwr1; ...SPI_RX bit is set
           mov   a, SPI_DATA     ; Move byte received into acc
           ret