51單片機+315M無線射頻模塊接受程序

sbit W_IN = P2^1;
sbit W_OUT = P2^0;

unsigned char w_data;//接收時用于存儲兩次上升沿之間的時長,發送時存儲前半周
unsigned char send_busy = 0;//存儲發送時后半周
unsigned char recv_timer = 0;
bit w_stat, last_w_stat;

unsigned char jiffies=0;
void clock_timer(void) interrupt 1 using 1{
if (send_busy){
if(w_data){
w_data--;
w_stat = 0;
}else{
send_busy--;
w_stat = 1;
}
W_OUT = w_stat;
}else{
w_stat = W_IN;
if (w_stat != last_w_stat){
last_w_stat = w_stat;
if (w_stat){
w_data = recv_timer;
recv_timer = 0;
}
}
if (~recv_timer)//if(recv_busy != 0xff)
recv_timer++;
}
jiffies++;
}

void clock_init(void){
jiffies = 0;
TMOD=0x02;
TH0=TL0=0x0ce;//12M,50us
//TH0=TL0=0x7a;//16M
//TH0=TL0=0x75;//16.59M
//TH0=TL0=0x72;//17M
//TH0=TL0=0x37;//24M
//TH0=TL0=0x47;//22.1844M, 100us
//TH0=TL0=0xa3;//22.1844M, 50us
EA=1;
ET0=1;

TR0=1;
}
void init_serialcomm(void)
{
SCON = 0x50; //SCON: serail mode 1, 8-bit UART, enable ucvr
TMOD |= 0x20; //TMOD: timer 1, mode 2, 8-bit reload
PCON |= 0x80; //SMOD=1;
TH1 = 0x0e6; //Baud:2400 fosc=11.0592MHz :f4
TL1 = 0x0e6;
//IE |= 0x90; //Enable Serial Interrupt
TR1 = 1; // timer 1 run
RI=0;
TI=1;
}

void serial_out(unsigned char d){
while(!TI);
TI=0;
SBUF=(d);
}

void send_string_com(unsigned char *str,int strlen)//串口程序
{ unsigned char sum;

unsigned char k=0;
//serial_out(02);
do
{ //sum^=*(str+k);
serial_out(*(str + k));
//serial_out(a);
k++;
} while(k < strlen);
//serial_out(sum);
//serial_out(e);
}

//等待指定長度的串行數據到達,超時值為每兩個字節之間的間隔時間而非等待整個串的時間.
//超時單位為time_out * 100uS
bit wait_serial(unsigned char *p, unsigned char len, unsigned char time_out){
unsigned int time=jiffies;
unsigned char n=0;
do{
if (RI){
p[n++]=SBUF;
RI=0;
if(n==len)
return 0;
time=jiffies;
}
}while(jiffies-time < time_out);
return 1;
}

sys_init(){
clock_init();
init_serialcomm();
}

//=============================================================
//發送程序 開始
//=============================================================

#define PULS_0_WIDTH 8//低電平脈寬
#define PULS_1_WIDTH 16//高電平脈寬
#define PULS_HEAD_WIDTH 8//前導信號脈寬
#define PULS_START_WIDTH 24//引導信號脈寬
#define PULS_STOP_WIDTH 8//結束碼脈寬

#define PULS_HEAD_COUNTS 16//前導信號長度

unsigned char send_buf[16];
#define send_byts send_buf[0]//剩余字節數,發送完后為0
unsigned char sending_byte;//當前正在發送的字節
unsigned char send_byte_p;//已發送字節數(含正在發送的字節)
unsigned char send_bit_p;//當前正在發送的字節已發送位數(含正在發送的位)

#define SEND_PROGRESSING 0x41
#define SEND_FAILED 0x21
#define SEND_SUCCESS 0x31
unsigned char send_stat = 0;//發送程序當前狀態,為0時正常
unsigned char head_counts;//前導信號計數器(包括引導信號)

void start_send(){
send_byte_p = 0;
send_bit_p = 0;
send_stat = SEND_PROGRESSING;
head_counts = 16;
}

#define START_SEND(byts) send_buf[0]=byts;send_byts=byts;start_send()

//發送前應清除send_byte_p,send_bit_p,send_stat,并設置send_byts
//發送過程中可根據send_byts的值得到剩余字節數,根據send_byte_p的值得到已發送字節數.注意,將正在發送的字節當作已發送完畢.
//發送過程中可根據send_stat的值得到發送狀態.
//發送完成后,send_byts和send_bit_p的值都為0.
#define SEND_PULS(x) w_data=send_busy=(x>>1)
void send(){
//下面兩行在wirless()中已經執行過了,所以無需寫上
//if (send_stat != SEND_PROGRESSING)
//return;

if (!send_busy){
if(send_byts || send_bit_p){
if (head_counts){
head_counts--;
if(head_counts)
SEND_PULS(PULS_HEAD_WIDTH);
else
SEND_PULS(PULS_START_WIDTH);
}else{
if (send_bit_p == 0){
sending_byte = send_buf[send_byte_p];
send_byte_p++;
send_byts--;
send_bit_p = 8;
}

if(sending_byte & 0x80){
SEND_PULS(PULS_1_WIDTH);
}else{
SEND_PULS(PULS_0_WIDTH);
}

sending_byte <<= 1;
send_bit_p--;
}
}else{
SEND_PULS(PULS_STOP_WIDTH);
send_stat = SEND_SUCCESS;
}
}
return;
}
//=============================================================
//發送程序 結束
//=============================================================

//=============================================================
//接收程序 開始
//=============================================================

unsigned char recv_buf[16];
#define recv_byts recv_buf[0]//應收到字節數,由每個包的第一個字節指定
unsigned char recving_byte;//當前正在接收的字節
unsigned char recv_byte_p;//已收到字節數(不含正在接收的字節)
unsigned char recv_bit_p;//當前正在接收的字節等待接收位數(不含正在接收的位)

#define RECV_FAILED 0x31
#define RECV_SUCCESS 0x41

unsigned char recv_stat = 0; //接收程序當前狀態,為0時正常
unsigned char recv_step = 0;//引導脈沖標志,為0時等待引導,為1時等待數據

#define TEST_PULS(puls_in, puls_type) (puls_in > puls_type - PULS_0_WIDTH / 2 && puls_in < puls_type + PULS_0_WIDTH / 2)

#define HEAD_NEED_RECIVED 8
void recv(){
unsigned puls_width;

if ((recv_stat == RECV_SUCCESS) || !w_data)
return;

puls_width = w_data;
w_data = 0;

#if 0//輸出脈寬
serial_out(puls_width);
//printhex(puls_width);
#endif

if (recv_step < HEAD_NEED_RECIVED){
if(TEST_PULS(puls_width, PULS_HEAD_WIDTH)){
recv_step++;
}else{
recv_step = 0;
}
}else if (recv_step == HEAD_NEED_RECIVED){
if(TEST_PULS(puls_width, PULS_START_WIDTH)){
serial_out(0xbb);
recv_byte_p = 0;
recv_bit_p = 8;
recv_stat = 0;
recv_step++;
}else{
if(!TEST_PULS(puls_width, PULS_HEAD_WIDTH)){
recv_step = 0;
}
}
}else{
//serial_out(puls_width);
recving_byte <<= 1;
if(TEST_PULS(puls_width, PULS_0_WIDTH)){
recving_byte &= 0xfe;
}else if(TEST_PULS(puls_width, PULS_1_WIDTH)){
recving_byte |= 1;
}else{
serial_out(puls_width);
recv_step = 0;
serial_out(0xaa);
return;
}
recv_bit_p--;
if(recv_bit_p == 0){//接收完一字節
recv_bit_p = 8;
//serial_out(recving_byte);//輸出接收到的字符
recv_buf[recv_byte_p] = recving_byte;
recv_byte_p++;
if(recv_byte_p == recv_byts){
recv_step = 0;
recv_stat = RECV_SUCCESS;
}
}
}
}

//=============================================================
//接收程序 結束
//=============================================================

#define SEND_DELAY_TIME 20//防碰撞延遲(單位：毫秒)
unsigned char send_delay = SEND_DELAY_TIME;
#define VALID_PULS_COUNT 10
unsigned char valid_puls_counts = VALID_PULS_COUNT;

//碰撞檢測在該函數中實現.由于無線模塊本身的限制,碰撞檢測為非完全檢測,只能在發送前
//檢測是否有其它單元在使用信道,在發送過程中受到的碰撞干擾是無法檢測到的.經測試,效果還行
void wirless(){
if (send_stat == SEND_PROGRESSING && send_delay == 0){
send();
if (send_stat == SEND_SUCCESS)
send_delay = SEND_DELAY_TIME;
}else{
recv();
if (recv_step > HEAD_NEED_RECIVED)//如果檢測到當前有其它單元正在發送，繼續等待
send_delay = SEND_DELAY_TIME;
else{
if(TEST_PULS(w_data, PULS_0_WIDTH)//如果檢測到當前有其它單元正在發送，繼續等待
|| TEST_PULS(w_data, PULS_1_WIDTH)
//|| TEST_PULS(w_data, PULS_HEAD_WIDTH)
|| TEST_PULS(w_data, PULS_START_WIDTH)
//|| TEST_PULS(w_data, PULS_STOP_WIDTH)
){
if (valid_puls_counts)
valid_puls_counts--;
else
send_delay = SEND_DELAY_TIME;
}else{
valid_puls_counts = VALID_PULS_COUNT;
}
}
}
}