平台:从网上买的X86平台(baytrail -D (cerelon J1900))
Baytrail平台自带两个串口,基本上就是低端台式机的配置
串口也是同台式机一样
问题:这里将这个X86平台(baytrail cerelon J1900)当成从机设备,
将其接到PC的串口上,一直无输出
解决:串口线两端都是母头,也就是说是直连的,那么这样,baytrail的tx直接与PC的tx相接
所以调了很久都没有任何输出,问题就在于BYT的TX与PC的TX相接,导致PC上看不到BYT设备的输出
所以,调串口设备,一定要注意需要使用交叉线还是直连线,或者说要注意收和发是否对应
另外,上串口测试代码,这也是appbox的一个例程:
#include <stdio.h> #include <ctype.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <errno.h> #include <fcntl.h> #include <time.h> #include <dirent.h> #include <assert.h> #include <linux/unistd.h> #include <pthread.h> #include <semaphore.h> #include <signal.h> #include <termios.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <linux/ioctl.h> #include <sys/times.h> #include <sys/time.h> #include <sys/sysinfo.h> #include <net/if.h> #include <net/if_arp.h> #include <net/route.h> #include <linux/if_ether.h> #include <arpa/inet.h> #include <linux/sockios.h> #include <sys/mman.h> /* 平台:从网上买的X86平台(baytrail -D (cerelon J1900)) Baytrail平台自带两个串口,基本上就是低端台式机的配置 串口也是同台式机一样 问题:这里将这个X86平台(baytrail cerelon J1900)当成从机设备, 将其接到PC的串口上,一直无输出 解决:串口线两端都是母头,也就是说是直连的,那么这样,baytrail的tx直接与PC的tx相接 所以调了很久都没有任何输出,问题就在于BYT的TX与PC的TX相接,导致PC上看不到BYT设备的输出 另外,上串口测试代码,这也是appbox的一个例程: */ typedef unsigned int DWORD; typedef unsigned char BYTE; #define LINE_MAX_LENGTH 128 #define NAME_MAX_LENGTH 32 #define MAX_PATH_LENGTH 128 /// 串口属性结构 typedef struct COMM_ATTR { DWORD baudrate; ///< 实际的波特率值。 BYTE databits; ///< 实际的数据位数。 BYTE parity; ///< 奇偶校验选项,取comm_parity_t类型的枚举值。 BYTE stopbits; ///< 停止位数,取comm_stopbits_t类型的枚举值。 BYTE reserved; ///< 保留 } COMM_ATTR; /// 串口停止位类型 enum comm_stopbits_t { COMM_ONESTOPBIT, ///< 1 stop bit COMM_ONE5STOPBITS, ///< 1.5 stop bit COMM_TWOSTOPBITS ///< 2 stop bit }; /// 串口校验位类型 enum comm_parity_t { COMM_NOPARITY, ///< No parity COMM_ODDPARITY, ///< Odd parity COMM_EVENPARITY,///< Even parity COMM_MARK, ///< COMM_SPACE ///< }; typedef enum CommType { commBus_485 = 0x0001, commBus_422 = 0x0002, commBus_232 = 0x0004, } CommType; /// 串口操作中断类型 typedef enum CommPurgeFlags { commPurgeTxAbort = 0x0001, ///< 中止写操作 commPurgeRxAbort = 0x0002, ///< 中止读操作 commPurgeTxClear = 0x0004, ///< 清空输出缓冲 commPurgeRxClear = 0x0008 ///< 清空输入缓冲 } CommPurgeFlags; /// 串口停止位类型 typedef enum CommStopBit { commOneStopBit = 0, ///< 1 stop bit commOne5StopBits, ///< 1.5 stop bit commTwoStopBits //< 2 stop bit } CommStopBit; /// 串口校验位类型 typedef enum CommParityType { commNoParity = 0, ///< No parity commOddParity, ///< Odd parity commEvenParity, ///< Even parity commMarkParity, ///< Mark parity commSpaceParity ///< Space parity } CommParityType; /// 特殊串口标志 typedef enum CommSpecialFlag { commNormal = 0, commRedApple } CommSpecialFlag; /// 串口模式 typedef enum CommMode { commFullDuplex = 0, ///< 全双工 commSemiDuplex, ///< 半双工 } CommMode; int uartfd = -1; int FrontboardSetAttr(COMM_ATTR *ParmaAttribute_p) { struct termios Option; COMM_ATTR *Attribute_p = ParmaAttribute_p; memset(&Option, 0, sizeof(struct termios)); tcgetattr(uartfd, &Option); if(uartfd < 0) { printf("Index < 0 || UartSetAttributeEx.\n"); return -1; } cfmakeraw(&Option); switch(Attribute_p->baudrate) { case 50: cfsetispeed(&Option, B50); cfsetospeed(&Option, B50); break; case 75: cfsetispeed(&Option, B75); cfsetospeed(&Option, B75); break; case 110: cfsetispeed(&Option, B110); cfsetospeed(&Option, B110); break; case 134: cfsetispeed(&Option, B134); cfsetospeed(&Option, B134); break; case 150: cfsetispeed(&Option, B150); cfsetospeed(&Option, B150); break; case 200: cfsetispeed(&Option, B200); cfsetospeed(&Option, B200); break; case 300: cfsetispeed(&Option, B300); cfsetospeed(&Option, B300); break; case 600: cfsetispeed(&Option, B600); cfsetospeed(&Option, B600); break; case 1200: cfsetispeed(&Option, B1200); cfsetospeed(&Option, B1200); break; case 1800: cfsetispeed(&Option, B1800); cfsetospeed(&Option, B1800); break; case 2400: cfsetispeed(&Option, B2400); cfsetospeed(&Option, B2400); break; case 4800: cfsetispeed(&Option, B4800); cfsetospeed(&Option, B4800); break; case 9600: cfsetispeed(&Option, B9600); cfsetospeed(&Option, B9600); break; case 19200: cfsetispeed(&Option, B19200); cfsetospeed(&Option, B19200); break; case 38400: cfsetispeed(&Option, B38400); cfsetospeed(&Option, B38400); break; case 57600: cfsetispeed(&Option, B57600); cfsetospeed(&Option, B57600); break; case 115200: cfsetispeed(&Option, B115200); cfsetospeed(&Option, B115200); break; default: printf("Unsupported baudrate %d\n", Attribute_p->baudrate); return -1; } switch(Attribute_p->parity) { case commNoParity: // none Option.c_cflag &= ~PARENB; // disable parity Option.c_iflag &= ~INPCK; // disable parity check break; case commOddParity: // odd Option.c_cflag |= PARENB; // enable parity Option.c_cflag |= PARODD; // odd Option.c_iflag |= INPCK; // enable parity check break; case commEvenParity: // even Option.c_cflag |= PARENB; // enable parity Option.c_cflag &= ~PARODD; // even Option.c_iflag |= INPCK; // enable parity check break; case commMarkParity: Option.c_cflag |= PARENB; /* enable parity */ Option.c_cflag |= PARODD; /* parity bit is always 1 */ break; case commSpaceParity: Option.c_cflag |= PARENB; /* enable parity */ break; default: printf("Unsupported parity %d\n", Attribute_p->parity); return -1; } Option.c_cflag &= ~CSIZE; switch (Attribute_p->databits) { case 5: Option.c_cflag |= CS5; break; case 6: Option.c_cflag |= CS6; break; case 7: Option.c_cflag |= CS7; break; case 8: Option.c_cflag |= CS8; break; default: printf("Unsupported data bits %d\n", Attribute_p->databits); return -1; } Option.c_cflag &= ~CSTOPB; switch (Attribute_p->stopbits) { case commOneStopBit: Option.c_cflag &= ~CSTOPB; break; case commOne5StopBits: break; case commTwoStopBits: Option.c_cflag |= CSTOPB; break; default: printf("Unsupported stop bits %d\n", Attribute_p->stopbits); return -1; } Option.c_cc[VTIME] = 0; Option.c_cc[VMIN] = 1; tcflush(uartfd, TCIOFLUSH); if(tcsetattr(uartfd, TCSANOW, &Option) < 0) { printf("tcsetattr Failed.\n"); return -1; } return 0; } int FrontboardCreate(void) { char DeviceName[NAME_MAX_LENGTH] = {0}; int iFbUartIndex; COMM_ATTR UartAttribute; memset(&UartAttribute, 0, sizeof(UartAttribute)); if(uartfd > 0) { return 0; } iFbUartIndex = 0; snprintf(DeviceName, sizeof(DeviceName),"%s%d", "/dev/ttyS", iFbUartIndex); printf("DeviceName:%s\n", DeviceName); uartfd = open(DeviceName, O_RDWR); if(uartfd < 0) { printf("Open %s failed.\n", DeviceName); return -1; } UartAttribute.baudrate = 9600; UartAttribute.databits = 8; UartAttribute.parity = commNoParity; UartAttribute.stopbits = commOneStopBit; if(FrontboardSetAttr(&UartAttribute) < 0) { printf("UartSetAttributeEx Failed. \n"); return -1; } return 0; } int FrontboardDestory(void) { if(uartfd > 0) { close(uartfd); uartfd = -1; } return 0; } int FrontboardRead(void *pData, DWORD nBytes) { int ReadLength = 0; int ReadPosition = 0; if(NULL == pData || nBytes < 0) { printf("Invalid Params, NULL == pData or nBytes < 0.\n"); return -1; } memset(pData, 0, nBytes); while(0 != nBytes) { ReadLength = read(uartfd, pData + ReadPosition, nBytes); if(ReadLength < 0) { printf("read Failed, ReadLength < 0.\n"); return -1; } ReadPosition += ReadLength; nBytes -= ReadLength; } return ReadPosition; } int FrontboardWrite(void *pData, DWORD nBytes) { int WriteLength = 0; int WritePosition = 0; if(NULL == pData || nBytes < 0) { printf("Invalid Params, NULL == pData || nBytes < 0.\n"); return -1; } while(0 != nBytes) { WriteLength = write(uartfd, pData + WritePosition, nBytes); if(WriteLength < 0) { printf("write failed, nBytes:%d, WriteLength:%d\n", nBytes, WriteLength); return -1; } WritePosition += WriteLength; nBytes -= WriteLength; } return WritePosition; } int main(int argc, char *argv[]) { unsigned char pData[8] = {0}; pData[0] = 'a'; pData[1] = 'b'; pData[2] = 'c'; pData[3] = 'd'; pData[4] = '\n'; FrontboardCreate(); while(1) { printf("frontboardwrite:\n"); FrontboardWrite((void*)pData, 8); sleep(1); } return 0; }
原文地址:http://blog.csdn.net/xiangpingli/article/details/41149731