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First test of re-structured modulation.
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@darksidelemm
darksidelemm committed Mar 17, 2018
1 parent 3fec4a1 commit c7912d5
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Showing 2 changed files with 137 additions and 50 deletions.
8 changes: 6 additions & 2 deletions f_rtty.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,16 +2,20 @@

uint8_t start_bits;
rttyStates send_rtty(char *buffer) {
// Step through a supplied charater bit by bit (with each function call), and return
// the current state (one, zero, end)
static uint8_t nr_bit = 0;
nr_bit++;
//
if (start_bits){
start_bits--;
return rttyOne;
}

// Start bit.
if (nr_bit == 1) {
return rttyZero;
}
// Data bits
if (nr_bit > 1 && nr_bit < (RTTY_7BIT ? 9 : 10)) {
if ((*(buffer) >> (nr_bit - 2)) & 0x01) {
return rttyOne;
Expand All @@ -23,7 +27,7 @@ rttyStates send_rtty(char *buffer) {
#ifdef RTTY_7BIT
nr_bit++;
#endif

// Stop Bit
if (nr_bit == 10) {
return rttyOne;
}
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179 changes: 131 additions & 48 deletions main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,32 +21,48 @@
#include "delay.h"
#include "aprs.h"

char callsign[15] = {CALLSIGN};
// IO Pins Definitions. The state of these pins are initilised in init.c
#define GREEN GPIO_Pin_7 // Inverted
#define RED GPIO_Pin_8 // Non-Inverted (?)


#define GREEN GPIO_Pin_7
#define RED GPIO_Pin_8
// Transmit Modulation Switching
#define STARTUP 0
#define RTTY 1
#define FSK_4 2
#define FSK_2 3
volatile int current_mode = STARTUP;

// Telemetry Data to Transmit - used in RTTY & MFSK packet generation functions.
unsigned int send_count; //frame counter
char status[2] = {'N'};
int voltage;
volatile int adc_bottom = 2000;
int8_t si4032_temperature;
GPSEntry gpsData;

volatile char flaga = 0; // GPS Status Flags
volatile int led_enabled = 1; // Flag to disable LEDs at altitude.
char callsign[15] = {CALLSIGN};
char status[2] = {'N'};
uint16_t CRC_rtty = 0x12ab; //checksum (dummy initial value)
char buf_rtty[200];

// Volatile Variables, used within interrupts.
volatile int adc_bottom = 2000;
volatile char flaga = 0; // GPS Status Flags
volatile int led_enabled = 1; // Flag to disable LEDs at altitude.

volatile unsigned char pun = 0;
volatile unsigned int cun = 10;
volatile unsigned char tx_on = 0;
volatile unsigned int tx_on_delay;
volatile unsigned char tx_enable = 0;
rttyStates send_rtty_status = rttyZero;
volatile char *rtty_buf;
volatile char *tx_buffer;
volatile uint16_t button_pressed = 0;
volatile uint8_t disable_armed = 0;

// Function Definitions
void collect_telemetry_data();
void send_rtty_packet();
void send_mfsk_packet();
uint16_t gps_CRC16_checksum (char *string);


Expand All @@ -63,6 +79,11 @@ void USART1_IRQHandler(void) {
}
}

//
// Symbol Timing Interrupt
// In here symbol transmission occurs.
//

void TIM2_IRQHandler(void) {
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
Expand All @@ -82,33 +103,62 @@ void TIM2_IRQHandler(void) {
button_pressed = 0;
}

if (button_pressed == 0) {
adc_bottom = ADCVal[1] * 1.1; // dynamical reference for power down level
}
if (button_pressed == 0) {
adc_bottom = ADCVal[1] * 1.1; // dynamical reference for power down level
}
}

if (tx_on) {
// RTTY Symbol selection logic.
send_rtty_status = send_rtty((char *) rtty_buf);
if (!disable_armed){
if (send_rtty_status == rttyEnd) {
if (led_enabled) GPIO_SetBits(GPIOB, RED);
if (*(++rtty_buf) == 0) {
tx_on = 0;
tx_on_delay = TX_DELAY / (1000/RTTY_SPEED);
tx_enable = 0;
//radio_disable_tx(); // Don't turn off the transmitter!
if(current_mode == RTTY){
send_rtty_status = send_rtty((char *) tx_buffer);

if (!disable_armed){
if (send_rtty_status == rttyEnd) {
if (led_enabled) GPIO_SetBits(GPIOB, RED);
if (*(++tx_buffer) == 0) {
tx_on = 0;
// Reset the TX Delay counter, which is decremented at the symbol rate.
tx_on_delay = TX_DELAY / (1000/RTTY_SPEED);
tx_enable = 0;
//radio_disable_tx(); // Don't turn off the transmitter!
}
} else if (send_rtty_status == rttyOne) {
radio_rw_register(0x73, RTTY_DEVIATION, 1);
if (led_enabled) GPIO_SetBits(GPIOB, RED);
} else if (send_rtty_status == rttyZero) {
radio_rw_register(0x73, 0x00, 1);
if (led_enabled) GPIO_ResetBits(GPIOB, RED);
}
} else if (send_rtty_status == rttyOne) {
radio_rw_register(0x73, RTTY_DEVIATION, 1);
if (led_enabled) GPIO_SetBits(GPIOB, RED);
} else if (send_rtty_status == rttyZero) {
radio_rw_register(0x73, 0x00, 1);
if (led_enabled) GPIO_ResetBits(GPIOB, RED);
}
} else if (current_mode == FSK_4) {
// 4FSK Symbol Selection Logic
// Get Symbol to transmit.

// Set Symbol.

// Halt modulation, reset inter-transmission timer.
tx_on = 0;
tx_on_delay = TX_DELAY / (1000/RTTY_SPEED);
tx_enable = 0;

} else if (current_mode == FSK_2) {
// 2FSK Symbol Selection Logic
// TODO

// Halt modulation, reset inter-transmission timer.
tx_on = 0;
tx_on_delay = TX_DELAY / (1000/RTTY_SPEED);
tx_enable = 0;
} else{
// Ummmm.
}
}

// Delay between Transmissions Logic.
// tx_on_delay is set at the end of a RTTY transmission above, and counts down
// at the interrupt rate. When it hits zero, we set tx_enable to 1, which allows
// the main loop to continue.
if (!tx_on && --tx_on_delay == 0) {
tx_enable = 1;
tx_on_delay--;
Expand Down Expand Up @@ -168,37 +218,46 @@ int main(void) {

// ADC configuration
radio_rw_register(0x0f, 0x80, 1);
rtty_buf = buf_rtty;
tx_buffer = buf_rtty;
tx_on = 0;
tx_enable = 1;

aprs_init();
radio_enable_tx();


while (1) {
// Don't do anything until the previous transmission has finished.
if (tx_on == 0 && tx_enable) {
send_rtty_packet();
if (current_mode == STARTUP){
// Grab telemetry information.
collect_telemetry_data();

// Now Startup a RTTY Transmission
current_mode = RTTY;
send_rtty_packet();
} else if (current_mode == RTTY){
// We've just transmitted a RTTY packet, now configure for 4FSK.
current_mode = FSK_4;
send_mfsk_packet();
} else {
// We've finished the 4FSK transmission, grab new data.
current_mode = STARTUP;
}
} else {
NVIC_SystemLPConfig(NVIC_LP_SEVONPEND, DISABLE);
__WFI();
}
}
}

void send_rtty_packet() {
start_bits = RTTY_PRE_START_BITS;
int8_t si4032_temperature = radio_read_temperature();

void collect_telemetry_data() {

send_count++;
si4032_temperature = radio_read_temperature();
voltage = ADCVal[0] * 600 / 4096;
GPSEntry gpsData;
ublox_get_last_data(&gpsData);

uint8_t lat_d = (uint8_t) abs(gpsData.lat_raw / 10000000);
uint32_t lat_fl = (uint32_t) abs(abs(gpsData.lat_raw) - lat_d * 10000000) / 1000;
uint8_t lon_d = (uint8_t) abs(gpsData.lon_raw / 10000000);
uint32_t lon_fl = (uint32_t) abs(abs(gpsData.lon_raw) - lon_d * 10000000) / 1000;

if (gpsData.fix >= 3) {
flaga |= 0x80;
// Disable LEDs if altitude is > 1000m. (Power saving? Maybe?)
Expand All @@ -212,17 +271,26 @@ void send_rtty_packet() {
flaga &= ~0x80;
led_enabled = 1; // Enable LEDs when there is no GPS fix (i.e. during startup)

// Null out lat/long data to avoid spamming invalid positions all over the map.
lat_d = 0;
lat_fl = 0;
lon_d = 0;
lon_fl = 0;
// Null out lat / lon data to avoid spamming invalid positions all over the map.
gpsData.lat_raw = 0;
gpsData.lon_raw = 0;
}
}


void send_rtty_packet() {
// Write a RTTY packet into the tx buffer, and start transmission.

// Convert raw lat/lon values into degrees and decimal degree values.
uint8_t lat_d = (uint8_t) abs(gpsData.lat_raw / 10000000);
uint32_t lat_fl = (uint32_t) abs(abs(gpsData.lat_raw) - lat_d * 10000000) / 1000;
uint8_t lon_d = (uint8_t) abs(gpsData.lon_raw / 10000000);
uint32_t lon_fl = (uint32_t) abs(abs(gpsData.lon_raw) - lon_d * 10000000) / 1000;

// HORUS RTTY compatible sentences.
// Produce a RTTY Sentence (Compatible with the existing HORUS RTTY payloads)
sprintf(buf_rtty, "$$$$$%s,%d,%02u:%02u:%02u,%s%d.%04ld,%s%d.%04ld,%ld,%ld,%d,%d,%d",
callsign,
send_count,
callsign,
send_count,
gpsData.hours, gpsData.minutes, gpsData.seconds,
gpsData.lat_raw < 0 ? "-" : "", lat_d, lat_fl,
gpsData.lon_raw < 0 ? "-" : "", lon_d, lon_fl,
Expand All @@ -232,15 +300,30 @@ void send_rtty_packet() {
voltage*10,
si4032_temperature
);
// Calculate and append CRC16 checksum to end of sentence.
CRC_rtty = gps_CRC16_checksum(buf_rtty + 5);
sprintf(buf_rtty, "%s*%04X\n", buf_rtty, CRC_rtty & 0xffff);
rtty_buf = buf_rtty;

// Point the TX buffer at the temporary RTTY packet buffer.
tx_buffer = buf_rtty;

// Enable the radio, and set the tx_on flag to 1.
start_bits = RTTY_PRE_START_BITS;
radio_enable_tx();
tx_on = 1;
// From here the timer interrupt handles things.
}

send_count++;

void send_mfsk_packet(){
// Generate a MFSK Binary Packet

// Enable the radio, and set the tx_on flag to 1.
radio_enable_tx();
tx_on = 1;
}


uint16_t gps_CRC16_checksum(char *string) {
uint16_t crc = 0xffff;
char i;
Expand Down

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