300 lines
8.6 KiB
C
300 lines
8.6 KiB
C
#ifndef _SERIAL_PORT_H_
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#define _SERIAL_PORT_H_
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char guessedSerialDevice[512] = {0};
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#ifdef _USE_WIN_API_
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#include <windows.h>
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#define SerialDeviceHandle HANDLE
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#define DEFAULT_SERIAL_DEVICE_NAME "COM1"
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#define INVALID_HANDLE INVALID_HANDLE_VALUE
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#ifdef NO_CLOSE
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static SerialDeviceHandle serH = INVALID_HANDLE;
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#endif
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// ideas: https://stackoverflow.com/questions/1388871/how-do-i-get-a-list-of-available-serial-ports-in-win32
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static void serialDeviceGuessName(char** deviceName) {
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char buf[64 * 1024] = {0};
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int size = QueryDosDevice(NULL, buf, 64 * 1024);
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int topComNum = 0;
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// buffer was filled in
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if (size > 0) {
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char* text = buf;
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int pos = 0;
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int start = 0;
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// search the received buffer for COM string
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while (pos < size) {
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int nameLen;
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start = pos;
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// find the string terminator
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while(pos < size && buf[pos] != 0) {
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pos++;
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}
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nameLen = pos - start;
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// COM port found
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if (nameLen >= 4 && nameLen <=6 && 0 == strncmp(text, "COM", 3) && text[3] >= '0' && text[3] <= '9') {
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int comNum = atoi(text + 3);
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if (comNum > topComNum) {
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topComNum = comNum;
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strcpy(guessedSerialDevice, text);
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}
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}
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pos++;
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text = &buf[pos];
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}
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// if we have found a COM port then pass it back as the result
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if (topComNum > 0) {
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*deviceName = guessedSerialDevice;
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}
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}
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}
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// https://www.xanthium.in/Serial-Port-Programming-using-Win32-API
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static inline SerialDeviceHandle serialDeviceOpen(char* deviceName) {
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SerialDeviceHandle h;
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#ifdef NO_CLOSE
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if (serH != INVALID_HANDLE) {
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return serH;
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}
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#endif
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h = CreateFile(
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deviceName, //port name
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GENERIC_READ | GENERIC_WRITE, //Read/Write
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0, // No Sharing
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NULL, // No Security
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OPEN_EXISTING,// Open existing port only
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0, // Non Overlapped I/O
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NULL); // Null for Comm Devices
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if (h != INVALID_HANDLE) {
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BOOL result;
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COMMTIMEOUTS timeouts = { 0 };
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DCB dcbSerialParams = { 0 }; // Initializing DCB structure
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dcbSerialParams.DCBlength = sizeof(dcbSerialParams);
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result = GetCommState(h, &dcbSerialParams);
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if (!result) {
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return INVALID_HANDLE;
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}
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dcbSerialParams.BaudRate = CBR_57600; // Setting BaudRate
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dcbSerialParams.ByteSize = 8; // Setting ByteSize = 8
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dcbSerialParams.StopBits = ONESTOPBIT;// Setting StopBits = 1
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dcbSerialParams.Parity = NOPARITY; // Setting Parity = None
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dcbSerialParams.fOutxCtsFlow = FALSE;
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dcbSerialParams.fOutxDsrFlow = FALSE;
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dcbSerialParams.fDtrControl = DTR_CONTROL_DISABLE;
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dcbSerialParams.fOutX = FALSE;
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dcbSerialParams.fInX = FALSE;
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dcbSerialParams.fRtsControl = RTS_CONTROL_DISABLE;
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dcbSerialParams.fBinary = TRUE;
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result = SetCommState(h, &dcbSerialParams);
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if (!result) {
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return INVALID_HANDLE;
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}
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timeouts.ReadIntervalTimeout = 30; // in milliseconds
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timeouts.ReadTotalTimeoutConstant = 30; // in milliseconds
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timeouts.ReadTotalTimeoutMultiplier = 10; // in milliseconds
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timeouts.WriteTotalTimeoutConstant = 50; // in milliseconds
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timeouts.WriteTotalTimeoutMultiplier = 10; // in milliseconds
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result = SetCommTimeouts(h, &timeouts);
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if (!result) {
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return INVALID_HANDLE;
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}
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//ensure no leftover bytes exist on the serial line
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result = PurgeComm(h, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);
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#ifdef NO_CLOSE
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serH = h;
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#endif
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return h;
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} else {
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return INVALID_HANDLE;
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}
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}
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void serialDeviceCheckName(char* name, int maxSize) {
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int nameLen = strlen(name);
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//convert comxx to COMxx
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if (strncmp(name, "com", 3) == 0 && (nameLen > 3 && name[3] >= '0' && name[3] <= '9')) {
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name[0] = 'C';
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name[1] = 'O';
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name[2] = 'M';
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}
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// convert COMxx and higher to \\\\.\\COMxx
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if (strncmp(name, "COM", 3) == 0 && (nameLen > 4 && name[3] >= '0' && name[3] <= '9')) {
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if (nameLen + 4 < maxSize) {
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int i;
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for (i = nameLen - 1; i >= 0; i--) {
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name[ i + 4] = name[i];
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}
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name[0] = '\\';
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name[1] = '\\';
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name[2] = '.';
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name[3] = '\\';
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}
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}
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}
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static inline void serialDeviceClose(SerialDeviceHandle deviceHandle) {
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#ifndef NO_CLOSE
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CloseHandle(deviceHandle);
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#endif
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}
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static inline int serialDeviceWrite(SerialDeviceHandle deviceHandle, char* buffer, int bytesToWrite) {
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DWORD written = 0;
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WriteFile(deviceHandle, buffer, bytesToWrite, &written, NULL);
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return (int) written;
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}
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static inline int serialDeviceRead(SerialDeviceHandle deviceHandle, char* buffer, int bytesToRead) {
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DWORD read = 0;
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ReadFile(deviceHandle, buffer, bytesToRead, &read, NULL);
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return (int) read;
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}
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#else
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#include <ctype.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <termios.h>
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#define SerialDeviceHandle int
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#define DEFAULT_SERIAL_DEVICE_NAME "/dev/ttyUSB0"
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#define INVALID_HANDLE -1
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#ifdef NO_CLOSE
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static SerialDeviceHandle serH = INVALID_HANDLE;
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#endif
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#ifdef _OSX_
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#define CHECK_SERIAL() (text != NULL)
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#define LIST_DEVICES "ls -1 /dev/tty.usb* /dev/tty.wchusb* 2>/dev/null"
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#else
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#define CHECK_SERIAL() (text != NULL && 0 == strncmp(text + 18, "usb-", 4))
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#define LIST_DEVICES "ls -1 /dev/serial/by-id/* 2>/dev/null"
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#endif
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// ideas: https://unix.stackexchange.com/questions/647235/debian-how-to-identify-usb-devices-with-similar-dev-tty-file
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// https://pubs.opengroup.org/onlinepubs/009696799/functions/popen.html
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static void serialDeviceGuessName(char** deviceName) {
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int i;
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char text[512];
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int topTtyNum = 0;
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FILE* f = popen(LIST_DEVICES, "r");
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if (f == NULL) {
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return;
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}
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i = 1;
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while (fgets(text, 512, f) != NULL) {
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// filer out non USB devices and prioritise those with Arduino name
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if (CHECK_SERIAL()) {
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int ttyNum = i;
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int textLen = strlen(text);
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// prefer Arduino over generic USB serial ports (does not work on OSX)
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if (textLen > 29 && 0 == strncmp(text + 18, "usb-Arduino", 11)) {
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ttyNum += 1000;
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}
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if (ttyNum > topTtyNum) {
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topTtyNum = ttyNum;
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strcpy(guessedSerialDevice, text);
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//strip the new-line trailing markers
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if (guessedSerialDevice[textLen - 1] == '\n' || guessedSerialDevice[textLen - 1] == '\r') {
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guessedSerialDevice[textLen - 1] = 0;
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}
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}
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}
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i++;
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}
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pclose(f);
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if (topTtyNum > 0) {
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*deviceName = guessedSerialDevice;
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}
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}
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static inline SerialDeviceHandle serialDeviceOpen(char* deviceName) {
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SerialDeviceHandle h;
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#ifdef NO_CLOSE
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if (serH != INVALID_HANDLE) {
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return serH;
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}
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#endif
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h = open(deviceName, O_RDWR | O_NOCTTY | O_NONBLOCK);
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if (h != INVALID_HANDLE) {
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//set the serial port parameters
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struct termios serial;
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memset(&serial, 0, sizeof(struct termios));
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cfsetispeed(&serial, B57600);
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cfsetospeed(&serial, B57600);
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serial.c_cflag |= CS8; // no parity, 1 stop bit
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serial.c_cflag |= CREAD | CLOCAL;
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if (0 != tcsetattr(h, TCSANOW, &serial)) {
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close(h);
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printf("Error: failed to set serial parameters %i, %s\n", errno, strerror(errno));
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return INVALID_HANDLE;
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}
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//ensure no leftover bytes exist on the serial line
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tcdrain(h);
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tcflush(h, TCIOFLUSH); //flush both queues
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#ifdef NO_CLOSE
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serH = h;
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#endif
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return h;
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} else {
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return INVALID_HANDLE;
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}
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}
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void serialDeviceCheckName(char* name, int maxSize) {
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//nothing to check
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}
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static inline void serialDeviceClose(SerialDeviceHandle deviceHandle) {
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#ifndef NO_CLOSE
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close(deviceHandle);
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#endif
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}
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static inline int serialDeviceWrite(SerialDeviceHandle deviceHandle, char* buffer, int bytesToWrite) {
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return write(deviceHandle, buffer, bytesToWrite);
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}
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static inline int serialDeviceRead(SerialDeviceHandle deviceHandle, char* buffer, int bytesToRead) {
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return read(deviceHandle, buffer, bytesToRead);
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}
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#endif
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#endif /* _SERIAL_PORT_H_ */
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