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MIC-E Encoder #7

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MIC-E Encoder #7

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b24e19b
Work in progress adding MIC-E format
tahpee Sep 3, 2017
851be68
Working(?) MIC-E encoder
Sep 3, 2017
5a21cf4
Working Mic-E Encoder
tahpee Sep 3, 2017
06d61c6
Reverted some of the memory reduction changes
tahpee Sep 3, 2017
bd5ad6e
Reverted more memory reduction changes
tahpee Sep 3, 2017
d9797bb
Added #defines for the MIC-E Standard Messages
tahpee Sep 10, 2017
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186 changes: 176 additions & 10 deletions LibAPRS/LibAPRS.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,14 +18,17 @@ AX25Call dst;
AX25Call path1;
AX25Call path2;

char CALL[7] = "NOCALL";
#define MAX_CALL_LENGTH 7
char CALL[MAX_CALL_LENGTH] = "NOCALL";
int CALL_SSID = 0;
char DST[7] = "APZMDM";
char DST[MAX_CALL_LENGTH] = "APZMDM";
int DST_SSID = 0;
char PATH1[7] = "WIDE1";
char PATH1[MAX_CALL_LENGTH] = "WIDE1";
int PATH1_SSID = 1;
char PATH2[7] = "WIDE2";
char PATH2[MAX_CALL_LENGTH] = "WIDE2";
int PATH2_SSID = 2;
uint8_t MICE_MSG;
uint8_t MICE_SSID;

AX25Call path[4];

Expand All @@ -39,6 +42,8 @@ uint8_t power = 10;
uint8_t height = 10;
uint8_t gain = 10;
uint8_t directivity = 10;
uint16_t speed;
uint16_t course;
/////////////////////////

// Message packet assembly fields
Expand All @@ -64,7 +69,7 @@ void APRS_poll(void) {
}

void APRS_setCallsign(char *call, int ssid) {
memset(CALL, 0, 7);
memset(CALL, 0, MAX_CALL_LENGTH);
int i = 0;
while (i < 6 && call[i] != 0) {
CALL[i] = call[i];
Expand All @@ -74,7 +79,7 @@ void APRS_setCallsign(char *call, int ssid) {
}

void APRS_setDestination(char *call, int ssid) {
memset(DST, 0, 7);
memset(DST, 0, MAX_CALL_LENGTH);
int i = 0;
while (i < 6 && call[i] != 0) {
DST[i] = call[i];
Expand All @@ -84,7 +89,7 @@ void APRS_setDestination(char *call, int ssid) {
}

void APRS_setPath1(char *call, int ssid) {
memset(PATH1, 0, 7);
memset(PATH1, 0, MAX_CALL_LENGTH);
int i = 0;
while (i < 6 && call[i] != 0) {
PATH1[i] = call[i];
Expand All @@ -94,7 +99,7 @@ void APRS_setPath1(char *call, int ssid) {
}

void APRS_setPath2(char *call, int ssid) {
memset(PATH2, 0, 7);
memset(PATH2, 0, MAX_CALL_LENGTH);
int i = 0;
while (i < 6 && call[i] != 0) {
PATH2[i] = call[i];
Expand All @@ -104,7 +109,7 @@ void APRS_setPath2(char *call, int ssid) {
}

void APRS_setMessageDestination(char *call, int ssid) {
memset(message_recip, 0, 7);
memset(message_recip, 0, 6);
int i = 0;
while (i < 6 && call[i] != 0) {
message_recip[i] = call[i];
Expand Down Expand Up @@ -175,6 +180,24 @@ void APRS_setDirectivity(int s) {
}
}

// Set the speed in knots. Valid speeds are 0-799 knots
void APRS_setSpeed(int s) {
if (s >= 0 && s < 800) {
speed = s;
} else {
speed = 0;
}
}

// Set the course, valid courses are 0-360 where 0 is unknown and 360 is due north
void APRS_setCourse(int c) {
if (c >= 0 && c <= 360) {
course = c;
} else {
course = 0;
}
}

void APRS_printSettings() {
Serial.println(F("LibAPRS Settings:"));
Serial.print(F("Callsign: ")); Serial.print(CALL); Serial.print(F("-")); Serial.println(CALL_SSID);
Expand Down Expand Up @@ -218,6 +241,149 @@ void APRS_sendPkt(void *_buffer, size_t length) {
ax25_sendVia(&AX25, path, countof(path), buffer, length);
}

// 3 bits of MIC-E message. Bit A is the most significant bit.
// If custom is set then we use the custom message bits when encoding
// Standard messages Custom Messages
// 0x07: M0: Off Duty C0: Custom-0
// 0x06: M1: En route C1: Custom-1
// 0x05: M2: In service C2: Custom-2
// 0x04: M3: Returning C3: Custom-3
// 0x03: M4: Committed C4: Custom-4
// 0x02: M5: Special C5: Custom-5
// 0x01: M6: Priority C6: Custom-6
// 0x00: Emergency Emergency
void APRS_set_mice_msg(uint8_t msg, bool custom) {
MICE_MSG = msg & 0x07;
// If custom message bits, store the custom flag in bit 7 of the MICE_MSG
if (custom) {
MICE_MSG |= 0x80;
}
}

void APRS_set_mice_ssid(uint8_t ssid) {
MICE_SSID = ssid & 0x0F;
}

uint8_t APRS_sendLoc_mice(void *_buffer, size_t length) {
uint8_t path_len;
uint8_t payloadLength = 9 + length;
uint8_t *packet = (uint8_t*)malloc(payloadLength);
// Sanity check the latitude and longtitude
if (latitude[7] != 'N' && latitude[7] != 'S') {
return 1;
}
if (longtitude[8] != 'E' && longtitude[8] != 'W') {
return 1;
}
// Build the Destination callsign with the latitude information
DST[0] = (latitude[0] & 0x0F) | 0x30;
if (MICE_MSG & 0x04) {
if (MICE_MSG & 0x80) {
DST[0] += 0x17; // Custom message bit
} else {
DST[0] += 0x20; // Standard message bit
}
}
DST[1] = (latitude[1] & 0x0F) | 0x30;
if (MICE_MSG & 0x02) {
if (MICE_MSG & 0x80) {
DST[1] += 0x17; // Custom message bit
} else {
DST[1] += 0x20; // Standard message bit
}
}
DST[2] = (latitude[2] & 0x0F) | 0x30;
if (MICE_MSG & 0x01) {
if (MICE_MSG & 0x80) {
DST[2] += 0x17; // Custom message bit
} else {
DST[2] += 0x20; // Standard message bit
}
}
DST[3] = (latitude[3] & 0x0F) | 0x30;
if (latitude[7] == 'N') { // North/South Latitude Indicator
DST[3] += 0x20;
}
DST[4] = (latitude[5] & 0x0F) | 0x30; // Use latitude[5] becuase latitude[4] is a .
// if (longtitude[0] == '1') { // If the longtitude is > 100, set this bit
// DST[4] += 0x20;
// }
DST[5] = (latitude[6] & 0x0F) | 0x30;
if (longtitude[8] == 'W') { // If the longtitude is > 100, set this bit
DST[4] += 0x20;
}

packet[0] = 0x60; // The ` character indicating valid GPS data
// Degrees. If longtitude > 100 the +100 longtitude bit is set in the Destination field, but only in
// certain circumstances, see http://www.aprs.org/doc/APRS101.PDF page 47
uint8_t lon_deg = ((longtitude[0] & 0x0F) * 100 + (longtitude[1] & 0x0F) * 10 + (longtitude[2] & 0x0F));
if (lon_deg < 10) {
packet[1] = 118 + lon_deg;
DST[4] += 0x20;
} else if (lon_deg < 100) {
packet[1] = 38 + lon_deg - 10;
} else if (lon_deg < 110) {
packet[1] = 108 + (lon_deg - 100);
DST[4] += 0x20;
} else {
packet[1] = 38 + (lon_deg - 110);
DST[4] += 0x20;
}

uint8_t lon_min = ((longtitude[3] & 0x0F) * 10) + (longtitude[4] & 0x0F);
if (lon_min < 10) {
packet[2] = 88 + lon_min;
} else {
packet[2] = 38 + lon_min - 10;
}
packet[3] = ((longtitude[6] & 0x0F) * 10) + (longtitude[7] & 0x0F) + 28;

// bytes 4, 5 and 6 encode the speed and course
// Page 50 of the APRS spec
packet[4] = (speed / 10) + 28; // 100's an 10's of knots
packet[5] = (speed % 10) * 10 + 32; // 1's of knots
if (course > 299) {
packet[5] += 3;
} else if (course > 199) {
packet[5] += 2;
} else if (course > 99) {
packet[5] += 1;
}
packet[6] = (course % 100) + 28;
packet[7] = (uint8_t)symbol;
packet[8] = (uint8_t)symbolTable;

if (MICE_SSID != 0) {
path_len = 0;
} else {
path_len = 4;
}

memcpy(dst.call, DST, 6);
dst.ssid = DST_SSID;

memcpy(src.call, CALL, 6);
src.ssid = CALL_SSID;

memcpy(path1.call, PATH1, 6);
path1.ssid = PATH1_SSID;

memcpy(path2.call, PATH2, 6);
path2.ssid = PATH2_SSID;

path[0] = dst;
path[1] = src;
path[2] = path1;
path[3] = path2;
if (length > 0) {
uint8_t *buffer = (uint8_t *)_buffer;
memcpy(&packet[9], buffer, length);
}
ax25_sendVia(&AX25, path, path_len, packet, payloadLength);
free(packet);
return 0;
}

// Dynamic RAM usage of this function is 30 bytes
void APRS_sendLoc(void *_buffer, size_t length) {
size_t payloadLength = 20+length;
Expand Down Expand Up @@ -303,7 +469,7 @@ void APRS_sendMsg(void *_buffer, size_t length) {
packet[12+length] = h+48;
packet[13+length] = d+48;
packet[14+length] = n+48;

APRS_sendPkt(packet, payloadLength);
free(packet);
}
Expand Down
15 changes: 15 additions & 0 deletions LibAPRS/LibAPRS.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,15 @@
#include "AFSK.h"
#include "AX25.h"

#define MICE_STD_MSG_OFF_DUTY 0x07
#define MICE_STD_MSG_EN_ROUTE 0x06
#define MICE_STD_MSG_IN_SERVICE 0x05
#define MICE_STD_MSG_RETURNING 0x04
#define MICE_STD_MSG_COMMITTED 0x03
#define MICE_STD_MSG_SPECIAL 0x02
#define MICE_STD_MSG_PRIORITY 0x01
#define MICE_STD_MSG_EMERGENCY 0x00

void APRS_init(int reference, bool open_squelch);
void APRS_poll(void);

Expand All @@ -28,11 +37,17 @@ void APRS_setPower(int s);
void APRS_setHeight(int s);
void APRS_setGain(int s);
void APRS_setDirectivity(int s);
void APRS_setSpeed(int s);
void APRS_setCourse(int c);

void APRS_sendPkt(void *_buffer, size_t length);
void APRS_sendLoc(void *_buffer, size_t length);
void APRS_sendMsg(void *_buffer, size_t length);
void APRS_msgRetry();
uint8_t APRS_sendLoc_mice(void *_buffer, size_t length);
void APRS_set_mice_ssid(uint8_t ssid);
void APRS_set_mice_msg(uint8_t msg, bool custom);


void APRS_printSettings();

Expand Down