Pi

Pin layout for Raspberry Pi 3

gpio readall
 +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 |   IN | 1 |  3 || 4  |   |      | 5v      |     |     |
 |   3 |   9 |   SCL.1 |   IN | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 0 | IN   | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | IN   | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 0 | IN   | GPIO. 1 | 1   | 18  |
 |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
 |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
 |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
 |  10 |  12 |    MOSI |   IN | 0 | 19 || 20 |   |      | 0v      |     |     |
 |   9 |  13 |    MISO |   IN | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
 |  11 |  14 |    SCLK |   IN | 0 | 23 || 24 | 1 | IN   | CE0     | 10  | 8   |
 |     |     |      0v |      |   | 25 || 26 | 1 | IN   | CE1     | 11  | 7   |
 |   0 |  30 |   SDA.0 |   IN | 1 | 27 || 28 | 1 | IN   | SCL.0   | 31  | 1   |
 |   5 |  21 | GPIO.21 |   IN | 1 | 29 || 30 |   |      | 0v      |     |     |
 |   6 |  22 | GPIO.22 |   IN | 1 | 31 || 32 | 0 | IN   | GPIO.26 | 26  | 12  |
 |  13 |  23 | GPIO.23 |   IN | 0 | 33 || 34 |   |      | 0v      |     |     |
 |  19 |  24 | GPIO.24 |   IN | 0 | 35 || 36 | 0 | IN   | GPIO.27 | 27  | 16  |
 |  26 |  25 | GPIO.25 |   IN | 0 | 37 || 38 | 0 | IN   | GPIO.28 | 28  | 20  |
 |     |     |      0v |      |   | 39 || 40 | 0 | IN   | GPIO.29 | 29  | 21  |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+

						

C program to interface with a USB GSM modem. Less than/greater than for #includes removed so it will display the file names!

/* 
 * Test of sending AT commands to USB GSM Modem at ttyACM0 using 
 * wiringPi
 */
#include stdio.h
#include string.h
#include errno.h
#include time.h

#include wiringPi.h
#include wiringSerial.h


void waitFor (unsigned int secs) {
    unsigned int retTime = time(0) + secs;   // Get finishing time.
    while (time(0) < retTime);               // Loop until it arrives.
}

#define OK       0
#define NO_INPUT 1
#define TOO_LONG 2
static int getLine (char *prmpt, char *buff, size_t sz) {
    int ch, extra;

    // Get line with buffer overrun protection.
    if (prmpt != NULL) {
        printf ("%s", prmpt);
        fflush (stdout);
    }
    if (fgets (buff, sz, stdin) == NULL)
        return NO_INPUT;

    // If it was too long, there'll be no newline. In that case, we flush
    // to end of line so that excess doesn't affect the next call.
    if (buff[strlen(buff)-1] != '\n') {
        extra = 0;
        while (((ch = getchar()) != '\n') && (ch != EOF))
            extra = 1;
        return (extra == 1) ? TOO_LONG : OK;
    }

    // Otherwise remove newline, and give string back to caller.
    buff[strlen(buff) -1] = '\0';
    return OK;
}
int main ()
{
	int fd;
	int rc;
	int dataAvailable = 0;

	char character;
    char buff[150];
 
	if ((fd = serialOpen ("/dev/ttyACM0", 460800)) < 0) {
		fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno));
		return 1 ;
	}

	if (wiringPiSetup () == -1) {
		fprintf (stdout, "Unable to start wiringPi: %s\n", strerror (errno));
		return 1 ;
	}

	while (1) {
		// Read in from the command line, no input and exit
		rc = getLine ("Enter AT Command > ", buff, sizeof(buff));
		if ((strlen(buff) == 0) || (rc == NO_INPUT) ) {
			printf("No input, exiting...\n");
			break;
		}
		else if (rc == TOO_LONG) {
			printf ("Input too long [%s], exiting...\n", buff);
			break;
		}
		else {
			printf ("OK [%s] %i\n", buff, strlen(buff));

			// Add '\r' at the end and terminate buff
			buff[strlen(buff)] = '\r';
			buff[strlen(buff) + 1] = '\0';

			serialPrintf(fd, buff);
			
			// Wait for a second
			waitFor(1);
			
			dataAvailable = serialDataAvail(fd);
			//printf("Data available: %i\n", dataAvailable);
			while (dataAvailable != 0) {
				character = (char)serialGetchar(fd);
				printf("%c", character);
				dataAvailable = serialDataAvail(fd);
			}
			printf("\n");
		}
	}

	printf("Program finished...\n");
	serialClose(fd);	
	return 0 ;
}