3是一個小型C程序,用於通過串行端口讀取和寫入十六進制數據。在閱讀中,我沒有問題,卜當我嘗試寫一個十六進制數據,因爲這:POSIX C串行端口寫入緩衝區
static const unsigned char cmdActuatorOn[] = "\x41\x54\x2B\x18\x12\x00\x12\x4B"
我看到寫功能通過串行端口只發送5個字節,所以,我想,這對於任何原因將十六進制數據切換爲「0x00」字符。 下面我串口設置:
int init_port(char const *const device)
{
int descriptor, result;
struct termios settings;
descriptor = open(device, O_RDWR | O_NOCTTY);
result = fcntl(descriptor, F_SETFL, O_NONBLOCK);
result = tcgetattr(descriptor, &settings);
settings.c_cflag &= ~PARENB;
settings.c_cflag &= ~CSTOPB;
settings.c_cflag &= ~CSIZE;
settings.c_cflag |= CS8;
settings.c_iflag |= IGNPAR;
settings.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXOFF | IXANY | INPCK);// raw data input mode
settings.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);// raw data output
settings.c_oflag &= ~OPOST;// setting timeouts
settings.c_cc[VMIN] = 1; // minimum number of chars to read in noncanonical (raw mode)
settings.c_cc[VTIME] = 5; // time in deciseconds to wait for data in noncanonical mode (raw mode)
cfsetispeed(&settings, B9600);
cfsetospeed(&settings, B9600);
result = tcsetattr(descriptor, TCSANOW, &settings);
return descriptor;
}
用於寫入數據的功能是:
int write_port(void const *const data, size_t const size)
{
unsigned char const *p = (unsigned char const *)data;
unsigned char const *const q = (unsigned char const *)data + size;
ssize_t n;
while (p < q) {
do {
n = write(port_descriptor, p, (size_t)(q - p));
} while (n == (ssize_t)-1 && errno == EINTR);
if (n == (ssize_t)-1 && errno == EWOULDBLOCK) {
/* Sleep for a millisecond, then retry. */
usleep(1000);
continue;
}
if (n == (ssize_t)-1)
return errno;
else
if (n < (ssize_t)1)
return EIO;
p += (size_t)n;
}
if (p != q)
return EIO;
return 0;
}
我打電話功能如下表寫入數據:
result = write_port(cmdActuatorOn, strlen(cmdActuatorOn));
這項工作很好他人二進制數據:
static const unsigned char cmdGetCoordAddress[] = "\x40\x04\x2B\x02\x08\x52\x41\x9D";
static const unsigned char cmdReadCoordChannelAddress[] = "\x43\x12\x0B\x07\x08";
static const unsigned char cmdReadCoordPanId[] = "\xAF\x50\x2B\x07\x09\x52\x49\x90";
在這種情況下,寫入函數在串行端口上寫入所有正確的字節。只有cmdActuatorOn不,所以我想這是0x00的問題。
我的錯誤在哪裏?我錯了串口配置?我將它設置爲使用原始模式...不正確?
非常感謝
以及如何將數據寫入端口? – isedev 2014-10-01 14:34:51
你不寫「十六進制數據」。你正在寫(從你的代碼的外觀)*二進制*數據,你*代表*在字符串中的十六進制。這不是「十六進制數據」。 – unwind 2014-10-01 14:38:42
..這個東西怎麼知道有5個字符,就像@isedev暗示的那樣?我希望答案不是'因爲空終止符',因爲,看數據.... – 2014-10-01 14:39:13