Controlling a Sparkfun thermal printer via C on Linux

/*=========================================================================== * Serial Port Programming in C (Serial Port Write) * Non Cannonical mode * Program writes a character to the serial port at 19200 bps 8N1 format *--------------------------------------------------------------------------- * original Programmer : Rahul.S * Date : 21-December-2014 *============================================================================ * altered by : Alex the Engineer * rtn VFRmedia the Rat's nest * Ipswich GB * to work with x86 netbook connected to Sparkfun thermal printer * via USB-TTL serial converter * Date : 2016-05-29 * 2016-05-30 : code recompiled to ZX-SL91 * (old Tosh amd64 laptop with busted keyboard repurposed as mini * server * ---------------------------------------------------------------------------- * 2016-06-10 : sourcecode formatting cleaned up a bit *============================================================================== /*-------------------------------------------------------------*/ /* termios structure - /usr/include/asm-generic/termbits.h */ /* use "man termios" to get more info about termios structure */ /*-------------------------------------------------------------*/ #include <stdio.h> #include <fcntl.h> /* File Control Definitions */ #include <string.h> /* strings */ #include <termios.h> /* POSIX Terminal Control Definitions */ #include <unistd.h> /* UNIX Standard Definitions */ #include <errno.h> /* ERROR Number Definitions */ /* global vars - probably shouldn't be hardcoded like this */ /* and some should be #defines to save memory */ /* but better than sticking them into the sourcecode */ int bytes_written = 0; /* Buffer containing characters to write into port */ char *write_buffer = "\x1b@\n\n\n" "\x1b\x0ertn\n" "telecommunicatie\x1b\x14\n" "printertest ZX-SL91\n" "\nAchtung! Achtung!\n" "The Goose is Loose!\n" "\x1d\x48\x03\n"; char *msg2= "\x1b@" "rtn :miauw naar de maan!\n\n\n\n\n"; char *barcode128n= "\x1d\x6bI"; char *item1= "2815 doedelzak"; char *item2= "9502 asbak "; char *item3= "7281 snakeoil "; char *lin_adv= "\n"; int main(void) { int fd; /*File Descriptor*/ printf("\n +----------------------------------+"); printf("\n | Serial Port Write |"); printf("\n +----------------------------------+"); /*------------------------------- Opening the Serial Port ------*/ /* Change /dev/ttyUSB0 to the one corresponding to your system */ fd = open("/dev/ttyUSB0",O_RDWR | O_NOCTTY | O_NDELAY); /* ttyUSB0 is the FT232 based USB2SERIAL Converter */ /* O_RDWR Read/Write access to serial port */ /* O_NOCTTY - No terminal will control the process */ /* O_NDELAY -Non Blocking Mode,Does not care about- */ /* -the status of DCD line,Open() returns immediatly */ if(fd == -1) { /* Error Checking */ perror("\n Error! in Opening ttyUSB0 "); return -1; } else perror("\n ttyUSB0 Opened Successfully "); /* set tty attrs 19200 8N1 */ struct termios SerialPortSettings; tcgetattr(fd, &SerialPortSettings); cfsetispeed(&SerialPortSettings,B19200); cfsetospeed(&SerialPortSettings,B19200); SerialPortSettings.c_cflag &= ~PARENB; SerialPortSettings.c_cflag &= ~CSTOPB; SerialPortSettings.c_cflag &= ~CSIZE; SerialPortSettings.c_cflag |= CS8; SerialPortSettings.c_cflag &= ~CRTSCTS; SerialPortSettings.c_cflag |= CREAD | CLOCAL; SerialPortSettings.c_iflag &= ~(IXON | IXOFF | IXANY); SerialPortSettings.c_iflag &= ~(ICANON | ECHO | ECHOE | ISIG); SerialPortSettings.c_oflag &= ~OPOST;/*No Output Processing*/ /* Set the attributes to the termios structure*/ if((tcsetattr(fd,TCSANOW,&SerialPortSettings)) != 0) { perror ("\n ERROR! in set attrs"); return -1; } else printf("\n ttyUSB0 set to 19200-8N1\n"); bytes_written = str_send(fd,write_buffer); printf("\n Sending these 3 barcode:\n%s\n%s\n%s\n",item1,item2,item3); bytes_written += bc128_send(fd,item1); bytes_written += bc128_send(fd,item2); bytes_written += bc128_send(fd,item3); bytes_written += str_send(fd,msg2); printf("\n %d Bytes written to ttyUSB0", bytes_written); printf("\n +----------------------------------+\n\n"); close(fd);/* Close the Serial port */ } /* str_send : write string of bytes to the serial port */ /* specified by fd */ /* returns number of bytes written */ int str_send (int fd, char *msg) { return write(fd,msg,strlen(msg)); } /* bc128_send : send code128 barcode from string */ /* create code 128 barcode - Achtung! uses fixed length sequence */ /* with hardcoded length of 14 (0x0e) sent to printer */ /* which must be specified as a string even though it is only 1 byte */ /* or wrong data is sent down the line */ /* and the barcodes do not print */ int bc128_send (int fd, char *barcode) { int bcount = 0; bcount += write(fd,barcode128n,3); bcount += write(fd,"\x0e",1); bcount += write(fd,barcode,14); return bcount; }