File content as of revision 0:566fc5f530fe:

#include "mbed.h"
#include "parser.h"
#include "string"
#include "list"

Serial pc(USBTX, USBRX);    // initialize RS232 via USB

DigitalOut prg_activity_led(LED1);     // some LED to show activity
DigitalOut rx_activity_led(LED2);
DigitalOut tx_activity_led(LED3);
DigitalOut message_led(LED4);

// we need some storage for the messages we want to send and receive
string singleSendMessageBuffer;
string singleReceiveMessageBuffer;
// and a buffer for those messages, until they are processed
list<string> sendMessagesBuffer;
list<string> receiveMessagesBuffer;


// Interupt Routine to read in data from serial port
void Rx_interrupt() {
    rx_activity_led=!rx_activity_led;
    // Loop just in case more than one character is in UART's receive FIFO buffer
    while (pc.readable()) {
        char c = pc.getc();
        unwrap_protocol(&c, &singleReceiveMessageBuffer, &receiveMessagesBuffer);
        // pc.putc(c); // echo
    }
    return;
}


// Interupt Routine to write out data to serial port
void Tx_interrupt() {
    char c;
    int finished = WRAP_SEND;
    int messageAvailable = !sendMessagesBuffer.empty();

    tx_activity_led=!tx_activity_led;

    // Loop to fill more than one character in UART's transmit FIFO buffer
    while (  pc.writeable() && messageAvailable && (finished == WRAP_SEND)) {
        finished = wrap_protocol( &c, &singleSendMessageBuffer, &sendMessagesBuffer );
        if (finished != WRAP_ABORT)
            pc.putc(c);
    }

    //tx_activity_led=0;
    return;
}


int main() {

    string sendString;

    pc.baud(115200);        // other high speed: 921600

    // Setup a serial interrupt function to receive data
    pc.attach(&Rx_interrupt, Serial::RxIrq);
    // Setup a serial interrupt function to transmit data
    pc.attach(&Tx_interrupt, Serial::TxIrq);
    // enable interrupt
    NVIC_EnableIRQ(UART1_IRQn);

    set_time(0);            // needed to initialize rtc

    while (1) {
        prg_activity_led = !prg_activity_led;       // toggle LED
        time_t seconds = time(NULL);    // get current time

        //printf("Time as a string = %s\r\n", ctime(&seconds));

        if (!receiveMessagesBuffer.empty()) {
            //pc.printf("\r\nMessage: %s\r\n", receiveMessagesBuffer.front().c_str());

            sendString = "Message '";
            sendString += receiveMessagesBuffer.front().c_str();
            sendString += "' received at ";
            sendString += ctime(&seconds);
            sendString += "\r";

            sendMessagesBuffer.push_back(sendString);
            receiveMessagesBuffer.pop_front();

        } else {
            //sendString = "Hallo Welt!\r\n";
            sendString = ctime(&seconds);
            sendString += "\r";
            sendMessagesBuffer.push_back(sendString);
        }
        
        
        // trigger sending interrupt
        char c;
        int finished = wrap_protocol( &c, &singleSendMessageBuffer, &sendMessagesBuffer );
        if (finished != WRAP_ABORT)
            pc.putc(c);

        wait(1); // wait and don't flood the RS232
    }
}