Diff: PPP-Blinky/ppp-blinky.cpp

Revision:

179:ba2b2ddd0da5

Parent:

178:3f17aa0ce5ce

Child:

180:fb1ab50e5e7a

--- a/PPP-Blinky/ppp-blinky.cpp	Thu Sep 07 16:22:20 2017 +0000
+++ b/PPP-Blinky/ppp-blinky.cpp	Mon Sep 11 14:58:43 2017 +0000
@@ -45,25 +45,25 @@
 // Using the second serial port will slow down packet response time
 // Note - the LPC11U24 does NOT have a second serial port
 
-#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
+#define SERIAL_PORT_MONITOR_YES /* change to SERIAL_PORT_MONITOR_YES for debug messages */
 
 // here we define the OPTIONAL, second debug serial port for various mbed target boards
 #ifdef SERIAL_PORT_MONITOR_YES
 #if defined(TARGET_LPC1768)
-Serial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
+RawSerial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
-Serial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
+RawSerial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
 #elif defined(TARGET_LPC11U24)
 #error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
-Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
+RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
 // change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
-Serial xx(p9, p10); // change this to YOUR board second serial port pin definition - and please send it to me if it works!!!
+RawSerial xx(p9, p10); // change this to YOUR board second serial port pin definition - and please send it to me if it works!!!
 #else
 #error Add your target board's second serial port here if you want to use debugging - or simply change SERIAL_PORT_MONITOR_YES to SERIAL_PORT_MONITOR_NO
 #endif
-#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
+#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
 #define debugPutc(x...) xx.putc(x)
 #define debugBaudRate(x...) xx.baud(x)
 #else
@@ -148,7 +148,7 @@
 // The modem baud rate should be set to 115200 baud
 // See instructions at the top.
 // On a typical mbed hardware platform this serial port is a USB virtual com port (VCP) and the USB serial driver is supplied by the board vendor.
-BufferedSerial pc(USBTX, USBRX, 100); // usb virtual com port for mbed hardware
+RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
 
 DigitalOut led1(LED1); // this led toggles when a packet is received
 
@@ -183,18 +183,23 @@
     ppp.ledState++;
 }
 
-/// returns 1 after a connect message, 0 at startup or after a disconnect message
+/// Returns 1 after a connect message, 0 at startup or after a disconnect message
 int connectedPpp()
 {
     return ppp.online;
 }
 
+/// Previously used to check for characters in receive buffer.
+/// Now just a stub.
+void checkPc() {};
+
+/// PPP serial port receive interrupt handler.
 /// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
 /// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
-void checkPc()
+void pppReceiveHandler()
 {
     char ch;
-    if ( pc.readable() ) {
+    while ( pc.readable() ) {
         int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
         if ( hd == ppp.rx.rtail ) {
             debugPrintf("\nReceive buffer full\n");
@@ -379,7 +384,8 @@
 }
 
 /// convert 4-byte ip address to 32-bit
-unsigned int ip( int a, int b, int c, int d){
+unsigned int ip( int a, int b, int c, int d)
+{
     return a<<24 | b<<16 | c<<8 | d;
 }
 
@@ -644,14 +650,17 @@
 /// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
 /// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
 /// See http://www.wikihow.com/Enable-IP-Routing.
-/// Also ensure that the firewall on the receiving machine has the receiving TCP/UDP port enabled.
+/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
+/// The netcat UDP receive command on the remote host would be: nc -ul 12345
 void sendUdpData()
 {
 #ifdef SERIAL_PORT_MONITOR_YES
-    if (xx.readable()) {
-        char inchar = xx.getc();
-        xx.putc( inchar ); // echo the char
-        sendUdp(ip(172,10,10,2), ip(192,168,0,120), 1, 12345, &inchar, 1); // send 1 byte message to 192.168.0.120:12345
+    if (ppp.online) {
+        if (xx.readable()) {
+            char inchar = xx.getc();
+            xx.putc( inchar ); // echo the received character on the debug serial port
+            sendUdp(ip(172,10,10,2), ip(192,168,0,109), 1, 12345, &inchar, 1); // send a 1 byte UDP message to a remote machine at IP 192.168.0.109:12345
+        }
     }
 #endif
 }
@@ -943,10 +952,8 @@
 {
 #ifdef SERIAL_PORT_MONITOR_YES
     if (v2) {
-        // IP header
         int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
         int headerSizeIp = 4 * ppp.ip->headerLength;  // size of ip header
-        // TCP header
         ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
         int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
         ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
@@ -1015,10 +1022,11 @@
             break;
         case TCP_FLAG_ACK | TCP_FLAG_PSH:
             if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
-                flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
+                flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // we have data, set the PSH flag
                 dataLen = httpResponse(tcpDataOut); // send an http response
             } else {
                 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
+                if (dataLen > 0) flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // if we have any data set the PSH flag
             }
             break;
         case TCP_FLAG_FIN:
@@ -1028,7 +1036,7 @@
             ack_out++; // for FIN flag we have to increase the sequence by 1
             break;
         default:
-            return; // ignore remaining packets
+            return; // ignore all other packets
     } // switch
 
     // The TCP flag handling is now done
@@ -1057,11 +1065,7 @@
     dumpHeaderIP(1); // dump outgoing IP header before sending the frame
     dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
     dumpDataTCP(1); // dump outgoing TCP data before sending the frame
-
-    for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time
-        checkPc(); // catch any incoming characters
-        wait_us(10); // wait less than 1 character duration at 115200
-    }
+    wait_ms(45); // 45 ms delay before sending frame - a typical internet delay time
     sendPppFrame(); // All preparation complete - send the TCP response
     if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
     memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
@@ -1250,9 +1254,9 @@
 /// Initialize PPP data structure and set serial port(s) baud rate(s)
 void initializePpp()
 {
-    pc.baud(115200); // USB serial port to pc
     debugBaudRate(115200); // baud rate for (optional) debug serial port
     debugPrintf("\x1b[2J\x1b[H\x1b[30mmbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
-    pppInitStruct(); // initialize all the PPP properties
+    pppInitStruct(); // initialize all the variables/properties/buffers
+    pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
+    pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
 }
-