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电梯直达

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发表于 2017-03-15 21:36 |只看该作者 |倒序浏览

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <sys/time.h>
#include <string.h>
#define TRUE 1
#define FALSE -1
int speed_arr[] = {B115200, B38400, B19200, B9600, B4800, B2400, B1200, B300,
B38400, B19200, B9600, B4800, B2400, B1200, B300,
};
int name_arr[] = {115200, 38400, 19200, 9600, 4800, 2400, 1200, 300,
38400, 19200, 9600, 4800, 2400, 1200, 300,
};
void set_speed(int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for (i = 0; i < sizeof(speed_arr) / sizeof(int); i++) {
if (speed == name_arr[i]) {
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0) {
perror("tcsetattr fd1");
}
return;
}
tcflush(fd, TCIOFLUSH);
}
}
int set_Parity(int fd, int databits, int stopbits, int parity)
{
struct termios options;
if (tcgetattr(fd, &options) != 0) {
perror("SetupSerial 1");
return (FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits) {
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr, "Unsupported data size\n");
return (FALSE);
}
switch (parity) {
case 'n':
case 'N':
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
options.c_iflag &= ~(ICRNL | IGNCR);
options.c_lflag &= ~(ICANON);
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD | PARENB);
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e':
case 'E':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'S':
case 's': /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
break;
default:
fprintf(stderr, "Unsupported parity\n");
return (FALSE);
}
switch (stopbits) {
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr, "Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != 'n') {
options.c_iflag |= INPCK;
}
options.c_cc[VTIME] = 150; // 15 seconds
options.c_cc[VMIN] = 0;
tcflush(fd, TCIFLUSH); /* Update the options and do it NOW */
if (tcsetattr(fd, TCSANOW, &options) != 0) {
perror("SetupSerial 3");
return (FALSE);
}
return (TRUE);
}
int main(int argc, char** argv)
{
int fd;
int nread;
int nwrite;
int n = 0;
char buffer[15];
char devname_head[10] = "/dev/";
char dev_name[20];
if (argc < 2) {
printf("Please input './test_uart ttySx'\n");
exit(1);
} else {
strcpy(dev_name, devname_head);
strcat(dev_name, argv[1]);
}
fd = open(dev_name, O_RDWR);
if (fd < 0) {
perror("error to open /dev/ttySx\n");
exit(1);
}
if (fd > 0) {
set_speed(fd, 115200);
} else {
printf("Can't Open Serial Port!\n");
exit(0);
}
if (set_Parity(fd, 8, 1, 'N') == FALSE) {
printf("Set Parity Error\n");
exit(1);
}
printf("\nWelcome to uart_test\n\n");
memset(buffer, 0, sizeof(buffer));
char test[15] = "hello world";
nwrite = write(fd, test, strlen(test));
if (nwrite < 0) {
printf("write error\n");
}
printf("Send test data------>%s\n", test);
while (1) {
nread = read(fd, &buffer[n], 1);
if (nread < 0) {
printf("read error\n");
}
printf("read char is -> %c \n", buffer[n]);
if (strlen(buffer) == strlen(test)) {
printf("Read Test Data finished,Read Test Data is------->%s\n", buffer);
memset(buffer, 0, sizeof(buffer));
printf("Send test data again------>%s\n", test);
write(fd, test, strlen(test));
n = 0;
sleep(1);
continue;
}
n++;
}
}

复制代码

上面代碼 hello world 字浮串導向 /dev/ttyS0

sudo ./test_uart ttyS0

我開cutecom 跟 minicom 想收hello world 字浮串但都收不到

baud rate 兩邊都是115200

可是我導向某個終端機

sudo ./test_uart pts/22 可以收到 hello world 字浮串
不明白為什麼 ttyS0 收不到字浮串

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