[BB方案]第六辑——编码实现

sjtitr

[BB方案]第六辑——编码实现 [复制链接]

本帖最后由 sjtitr 于 2014-6-17 11:29 编辑

总体来说，编码没什么难度的。从方案讲，从设计到编码也只需要抛砖引玉的做典型示例：

所以本辑只列举代码：
设计内容请参考[BB方案]第五辑——方案设计

首先是PHP，作为接收命令的起始点，我使用URL参数来接收要通过红外线发送的数据串：

<html>
<head>
<title>Test Pipe Page</title>
</head>
<body>
<?php
$str = $_REQUEST['str'];
$fp = @fopen("////tmp//irfifo", 'w');
echo $fp;
echo nl2br("\n");
$num = 0x5a;
$data = pack("H2", "5a");
echo @fwrite($fp, $data);
echo nl2br("\n");
$data = pack("C1", strlen($str)/2);
echo @fwrite($fp, $data);//д
echo nl2br("\n");
$data = pack("H*", $str);
echo @fwrite($fp,$data);//д
echo nl2br("\n");
fclose($fp);
echo nl2br("\n");
print("Hello World!");
echo nl2br("\n");
print("sjtitr");
echo nl2br("\n");
?>
<a href="test_pipe.php?str=00ff48b7"><-</a>
<a href="test_pipe.php?str=00ff4ab5">-></a>
</body>
</html>

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使用的时候，就像这样咯：test_pipe.php?str=00ff48b7

这样一来，C程序也很简单，目标是处理管道文件，然后启动pru：

#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <prussdrv.h>
#include <pruss_intc_mapping.h>
#define PRU_NUM 0
#define FIFO "/tmp/irfifo"
void prurun(char *buf)
{
unsigned int ret;
tpruss_intc_initdata pruss_intc_initdata = PRUSS_INTC_INITDATA;
prussdrv_init ();//Initialize the PRU
if (prussdrv_open(PRU_EVTOUT_0))//Open PRU Interrupt
{
printf("prussdrv_open open failed");
return;
}
prussdrv_pruintc_init(&pruss_intc_initdata);
{
prussdrv_pru_write_memory(PRUSS0_PRU0_DATARAM, 0, buf, buf[0]+1);
}
prussdrv_exec_program (PRU_NUM, "./prucode.bin");//Execute example on PRU
prussdrv_pru_wait_event (PRU_EVTOUT_0);//Waiting for this instruction: MOV r31.b0, PRU0_ARM_INTERRUPT+16
prussdrv_pru_clear_event (PRU0_ARM_INTERRUPT,0);
prussdrv_pru_disable (PRU_NUM);//Disable PRU and close memory mapping
prussdrv_exit ();
}
int main(int argc, char** argv)
{
char buf[64];
int fd;
int nread;
if((mkfifo(FIFO, O_CREAT|O_EXCL)<0) && (errno!=EEXIST))
{
printf("cannot create fifo\n");
}
fd = open(FIFO, O_RDONLY);
if(fd==-1)
{
printf("cannot open fifo\n");
exit(1);
}
while(1)
{
int i = 0;
memset(buf, 0, sizeof(buf));
read(fd, buf, 1);
if(buf[0]!=0x5A)
{
// printf("%X,", buf[0]);
continue;
}
read(fd, buf, 1);
if(buf[0] == 0)
{
break;
}
read(fd, &buf[1], buf[0]);
printf("%d: ", buf[0]);
while(i < buf[0])
{
i++;
printf("%X,",buf[i]);
}
printf("\n");
prurun(buf);
}
unlink(FIFO);
exit(0);
}

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最后是PRU程序，使用汇编语言完成，根据给下来的数据，执行红外编码的时序：

//prucode.p
.origin 0
.entrypoint START
//Refer to this mapping in the file - prussdrvincludepruss_intc_mapping.h
#define PRU0_ARM_INTERRUPT 19
#define CONST_PRUCFG C4
//Refer to AM335X Technical Reference Manual & BBB SRM
#define GPIO1 0x4804c000
#define GPIO_CLEARDATAOUT 0x190
#define GPIO_SETDATAOUT 0x194
START:
// Enable OCP master port
LBCO r0, CONST_PRUCFG, 4, 4
CLR r0, r0, 4 // Clear SYSCFG[STANDBY_INIT] to enable OCP master port
SBCO r0, CONST_PRUCFG, 4, 4
MOV r5, 0
LBBO r4, r5, 0, 1
AND r4, r4, 255
LEADER:
MOV r1, 340
CALL WAV_S
MOV r0, 450000
LEADER_T:
SUB r0, r0, 1
QBNE LEADER_T, r0, 0
NEXT_BYTE:
ADD r5, r5, 1
LBBO r6, r5, 0, 1
MOV r7, 8
NEXT_BIT:
MOV r1, 21
CALL WAV_S
AND r0, r6, 1<<7
QBNE BIT_1, r0, 0
BIT_0:
MOV r0, 56500
JMP BIT_T
BIT_1:
MOV r0, 169000
BIT_T:
SUB r0, r0, 1
QBNE BIT_T, r0, 0
LSL r6, r6, 1
SUB r7, r7, 1
QBNE NEXT_BIT, r7, 0
BYTE_OK:
SUB r4, r4, 1
QBNE NEXT_BYTE, r4, 0
STOP_S:
MOV r1, 21
CALL WAV_S
MOV r0, 5000000
STOP_T:
SUB r0, r0, 1
QBNE STOP_T, r0, 0
// Send notification to Host for program completion
MOV r31.b0, PRU0_ARM_INTERRUPT+16
// Halt the processor
HALT
WAV_S:
MOV r2, 1<<12
MOV r3, GPIO1 | GPIO_SETDATAOUT
SBBO r2, r3, 0, 4
MOV r0, 850
WAV_1:
SUB r0, r0, 1
QBNE WAV_1, r0, 0
MOV r2, 1<<12
MOV r3, GPIO1 | GPIO_CLEARDATAOUT
SBBO r2, r3, 0, 4
MOV r0, 1800
WAV_0:
SUB r0, r0, 1
QBNE WAV_0, r0, 0
SUB r1, r1, 1
QBNE WAV_S, r1, 0
RET

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OK。下一辑就是最后一辑了，我们来调试一下并实现一个场景，计划用视频说话~