From cd4bde37128d97a8f5c9976c1a71d491cd8bc2a6 Mon Sep 17 00:00:00 2001
From: clemibunge <clemibunge@gmail.com>
Date: Sat, 2 Jan 2021 22:31:27 +0100
Subject: [PATCH] Added RTTY Functionality

---
 src/pirtty/pirtty.cpp | 261 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 261 insertions(+)
 create mode 100644 src/pirtty/pirtty.cpp

diff --git a/src/pirtty/pirtty.cpp b/src/pirtty/pirtty.cpp
new file mode 100644
index 0000000..a497a38
--- /dev/null
+++ b/src/pirtty/pirtty.cpp
@@ -0,0 +1,261 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <cstring>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <math.h>
+#include <time.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+
+
+
+#include "../librpitx/src/librpitx.h"
+
+
+
+
+
+
+#define byte uint8_t
+
+
+int MARK = 2125;
+int SPACE = 1955;
+
+
+#define BAUDOT_SHIFT_LTRS 0x1f
+#define BAUDOT_SHIFT_FIGS 0x1b
+int BAUD_RATE = 22; // 45.45 baud
+
+
+char BAUDOT_FIGS[] = " \r\n1234567890-\a@!&#'()\"/:;?,.";
+char BAUDOT_LTRS[] = " \r\nQWERTYUIOPASDFGHJKLZXCVBNM";
+uint8_t baudot[] = {0x4,0x8,0x2,0x1d,0x19,0x10,0xa,0x1,0x15,0x1c,0xc,0x3,0xd,0x18,0x14,0x12,0x16,0xb,0x5,0x1a,0x1e,0x9,0x11,0x17,0xe,0xf,0x13,0x6,0x7};
+
+
+char TXTEXT[] = "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG";
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+int FileFreqTiming;
+
+ngfmdmasync *fmmod;
+static double GlobalTuningFrequency=00000.0;
+int FifoSize=10000; //10ms
+double frequencyshift=20000;
+bool running=true;
+
+void playtone(double Frequency,uint32_t Timing)//Timing in 0.1us
+{
+                uint32_t SumTiming=0;
+                SumTiming+=Timing%100;
+                if(SumTiming>=100)
+                {
+                        Timing+=100;
+                        SumTiming=SumTiming-100;
+                }
+                int NbSamples=(Timing/100);
+
+                while(NbSamples>0)
+                {
+                        usleep(10);
+                        int Available=fmmod->GetBufferAvailable();
+                        if(Available>FifoSize/2)
+                        {
+                                int Index=fmmod->GetUserMemIndex();
+                                if(Available>NbSamples) Available=NbSamples;
+                                for(int j=0;j<Available;j++)
+                                {
+                                        fmmod->SetFrequencySample(Index+j,Frequency);
+                                        NbSamples--;
+
+                                }
+                        }
+                }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+void rtty_txbit (bool bit)
+{
+    if(running) {
+        if (bit)
+        {
+            // MARK
+            playtone(MARK, BAUD_RATE*10000);
+        }
+        else
+        {
+            // SPACE
+            playtone(SPACE, BAUD_RATE*10000);
+        }
+    }
+
+}
+
+
+void rtty_txbyte (byte c)
+{
+
+
+    rtty_txbit (0); // Start bit
+    // Send bits for for char MSB first
+    for (byte i = 5; i > 0; --i)
+    {
+        if ((c & (1 << (i-1))) != 0)
+            rtty_txbit(1);
+        else
+            rtty_txbit(0);
+    }
+    rtty_txbit (1); // Stop bits
+    rtty_txbit (1);
+}
+
+
+
+void tx(char* string)
+{
+    char c = *string++;
+    byte index = 0, pos = 0;
+    byte shift = 0;
+
+    while (c != '\0')
+    {
+        char* index = strchr(BAUDOT_FIGS, c);
+        if(index != NULL) {
+            pos = index - BAUDOT_FIGS;
+            if(pos > 2 && shift != 1) {
+                shift = 1;
+                rtty_txbyte(BAUDOT_SHIFT_FIGS);
+            }
+            rtty_txbyte (baudot[pos]);
+        } else {
+            c = toupper(c);
+            index = strchr(BAUDOT_LTRS, c);
+            pos = index - BAUDOT_LTRS;
+            if(pos > 2 && shift != 2) {
+                shift = 2;
+                rtty_txbyte(31);
+            }
+            rtty_txbyte (baudot[pos]);
+        }
+        c = *string++;
+    }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+static void SendTones()
+{
+double basefreq = 0;
+double freq2 = 1100 + frequencyshift;
+//while(running)
+//{
+//        tone(1100);
+//}
+tx(TXTEXT);
+}
+
+static void
+terminate(int num)
+{
+    running=false;
+        fprintf(stderr,"Caught signal - Terminating %x\n",num);
+
+}
+
+int main(int argc, char **argv)
+{
+        float frequency=144.5e6;
+        if (argc > 3)
+        {
+
+
+                 frequency=atof(argv[1]);
+                 SPACE = atoi(argv[2]);
+                 MARK = SPACE + 170;
+                 strcpy(TXTEXT, argv[3]);
+
+        }
+        else
+        {
+                printf("usage : pirtty [frequency(Hz)] [Space Frequency(hz)] [text]\n");
+                exit(0);
+        }
+
+        for (int i = 0; i < 64; i++) {
+        struct sigaction sa;
+
+        std::memset(&sa, 0, sizeof(sa));
+        sa.sa_handler = terminate;
+        sigaction(i, &sa, NULL);
+    }
+
+        fmmod=new ngfmdmasync(frequency,100000,14,FifoSize);
+        SendTones();
+        delete fmmod;
+        return 0;
+}
+
+
+
+