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HamShield_KISS
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split phy out into its own fileset (bell202)

This commit is contained in:
Morgan Redfield 2018-06-03 21:25:22 -07:00
parent ba97bd4702
commit 591796fb99
7 changed files with 580 additions and 475 deletions
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216
src/packet.cpp → src/AX25.cpp
View File

@ -1,36 +1,46 @@
#include <Arduino.h>
#include "SimpleFIFO.h"
#include "packet.h"
#include "dds.h"
#include "AX25.h"
#include "bell202.h"
#include <util/atomic.h>
#define PHASE_BIT 8
#define PHASE_INC 1
#define PHASE_MAX (SAMPLEPERBIT * PHASE_BIT)
#define PHASE_THRES (PHASE_MAX / 2)
#define BIT_DIFFER(bitline1, bitline2) (((bitline1) ^ (bitline2)) & 0x01)
#define EDGE_FOUND(bitline) BIT_DIFFER((bitline), (bitline) >> 1)
#define PPOOL_SIZE 2
#define AFSK_SPACE 2200
#define AFSK_MARK 1200
// Timers
volatile unsigned long lastTx = 0;
volatile unsigned long lastTxEnd = 0;
volatile unsigned long lastRx = 0;
#define T_BIT ((unsigned int)(SAMPLERATE/BITRATE))
Bell202 afsk;
#ifdef PACKET_PREALLOCATE
SimpleFIFO<AFSK::Packet *,PPOOL_SIZE> preallocPool;
AFSK::Packet preallocPackets[PPOOL_SIZE];
SimpleFIFO<AX25::Packet *,PPOOL_SIZE> preallocPool;
AX25::Packet preallocPackets[PPOOL_SIZE];
#endif
void AFSK::Encoder::process() {
bool AX25::enabled() { return afsk.enabled(); }
void AX25::start(DDS *d) { afsk.start(d); }
// Determine what we want to do on this ADC tick.
void AX25::timer() {
static uint8_t tcnt = 0;
if(++tcnt == T_BIT && afsk.isSending()) {
PORTD |= _BV(6);
// Only run the encoder every 8th tick
// This is actually DDS RefClk / 1200 = 8, set as T_BIT
// A different refclk needs a different value
encoder.process();
tcnt = 0;
PORTD &= ~_BV(6);
} else {
decoder.process((int8_t)(ADCH - ADC_OFFSET));
}
}
void AX25::Encoder::process() {
// We're on the start of a byte position, so fetch one
if(bitPosition == 0) {
if(preamble) { // Still in preamble
@ -105,20 +115,15 @@ void AFSK::Encoder::process() {
// NRZI and AFSK uses toggling 0s, "no change" on 1
// So, if not a 1, toggle to the opposite tone
bool currentTone = afsk.encoderGetTone();
if(!currentBit)
currentTone = !currentTone;
if(currentTone == 0) {
PORTD |= _BV(7);
dds->setFrequency(AFSK_SPACE);
} else {
PORTD &= ~_BV(7);
dds->setFrequency(AFSK_MARK);
}
afsk.encoderSetTone(currentTone);
}
bool AFSK::Encoder::start() {
if(!done || sending) {
bool AX25::Encoder::start() {
if(!done || afsk.isSending()) {
return false;
}
@ -137,28 +142,26 @@ bool AFSK::Encoder::start() {
packet = 0x0; // No initial packet, find in the ISR
currentBytePos = 0;
maxTx = 3;
sending = true;
nextByte = 0;
dds->setFrequency(0);
dds->on();
afsk.encoderStart();
return true;
}
void AFSK::Encoder::stop() {
void AX25::Encoder::stop() {
randomWait = 0;
sending = false;
done = true;
dds->setFrequency(0);
dds->off();
afsk.encoderStop();
}
AFSK::Decoder::Decoder() {
AX25::Decoder::Decoder() {
// Initialize the sampler delay line (phase shift)
//for(unsigned char i = 0; i < SAMPLEPERBIT/2; i++)
// delay_fifo.enqueue(0);
}
bool AFSK::HDLCDecode::hdlcParse(bool bit, SimpleFIFO<uint8_t,AFSK_RX_FIFO_LEN> *fifo) {
bool AX25::HDLCDecode::hdlcParse(bool bit, SimpleFIFO<uint8_t,AFSK_RX_FIFO_LEN> *fifo) {
bool ret = true;
demod_bits <<= 1;
@ -205,70 +208,18 @@ bool AFSK::HDLCDecode::hdlcParse(bool bit, SimpleFIFO<uint8_t,AFSK_RX_FIFO_LEN>
return ret;
}
template <typename T, int size>
class FastRing {
private:
T ring[size];
uint8_t position;
public:
FastRing(): position(0) {}
inline void write(T value) {
ring[(position++) & (size-1)] = value;
}
inline T read() const {
return ring[position & (size-1)];
}
inline T readn(uint8_t n) const {
return ring[(position + (~n+1)) & (size-1)];
}
};
// Create a delay line that's half the length of the bit cycle (-90 degrees)
FastRing<uint8_t,(T_BIT/2)> delayLine;
// Handle the A/D converter interrupt (hopefully quickly :)
void AFSK::Decoder::process(int8_t curr_sample) {
// Run the same through the phase multiplier and butterworth filter
iir_x[0] = iir_x[1];
iir_x[1] = ((int8_t)delayLine.read() * curr_sample) >> 2;
iir_y[0] = iir_y[1];
iir_y[1] = iir_x[0] + iir_x[1] + (iir_y[0] >> 1) + (iir_y[0]>>3) + (iir_y[0]>>5);
// Place this ADC sample into the delay line
delayLine.write(curr_sample);
// Shift the bit into place based on the output of the discriminator
sampled_bits <<= 1;
sampled_bits |= (iir_y[1] > 0) ? 1 : 0;
// If we found a 0/1 transition, adjust phases to track
if(EDGE_FOUND(sampled_bits)) {
if(curr_phase < PHASE_THRES)
curr_phase += PHASE_INC;
else
curr_phase -= PHASE_INC;
}
// Move ahead in phase
curr_phase += PHASE_BIT;
// If we've gone over the phase maximum, we should now have some data
if(curr_phase >= PHASE_MAX) {
curr_phase %= PHASE_MAX;
found_bits <<= 1;
void AX25::Decoder::process(int8_t adc_val) {
bool parse_ready = afsk.decoderProcess(adc_val);
// If we have 3 bits or more set, it's a positive bit
register uint8_t bits = sampled_bits & 0x07;
if(bits == 0x07 || bits == 0x06 || bits == 0x05 || bits == 0x03) {
found_bits |= 1;
}
hdlc.hdlcParse(!EDGE_FOUND(found_bits), &rx_fifo); // Process it
if (parse_ready) {
hdlc.hdlcParse(!EDGE_FOUND(afsk.found_bits), &rx_fifo); // Process it
}
}
// This routine uses a pre-allocated Packet structure
// to save on the memory requirements of the stream data
bool AFSK::Decoder::read() {
bool AX25::Decoder::read() {
bool retVal = false;
if(!currentPacket) { // We failed a prior memory allocation
currentPacket = pBuf.makePacket(PACKET_MAX_LEN);
@ -350,42 +301,13 @@ bool AFSK::Decoder::read() {
return retVal; // This is true if we parsed a packet in this flow
}
#define AFSK_ADC_INPUT 2
void AFSK::Decoder::start() {
void AX25::Decoder::start() {
// Do this in start to allocate our first packet
currentPacket = pBuf.makePacket(PACKET_MAX_LEN);
/* ASSR &= ~(_BV(EXCLK) | _BV(AS2));
// Do non-inverting PWM on pin OC2B (arduino pin 3) (p.159).
// OC2A (arduino pin 11) stays in normal port operation:
// COM2B1=1, COM2B0=0, COM2A1=0, COM2A0=0
// Mode 1 - Phase correct PWM
TCCR2A = (TCCR2A | _BV(COM2B1)) & ~(_BV(COM2B0) | _BV(COM2A1) | _BV(COM2A0)) |
_BV(WGM21) | _BV(WGM20);
// No prescaler (p.162)
TCCR2B = (TCCR2B & ~(_BV(CS22) | _BV(CS21))) | _BV(CS20) | _BV(WGM22);
OCR2A = pow(2,COMPARE_BITS)-1;
OCR2B = 0;*/
// This lets us use decoding functions that run at the same reference
// clock as the DDS.
// We use ICR1 as TOP and prescale by 8
// Note that this requires the DDS to be started as well
TCCR1A = 0;
TCCR1B = _BV(CS11) | _BV(WGM13) | _BV(WGM12);
ICR1 = ((F_CPU / 8) / 9600) - 1; //TODO: get the actual refclk from dds
// NOTE: should divider be 1 or 8?
ADMUX = _BV(REFS0) | _BV(ADLAR) | AFSK_ADC_INPUT; // Channel AFSK_ADC_INPUT, shift result left (ADCH used)
DDRC &= ~_BV(AFSK_ADC_INPUT);
PORTC &= ~_BV(AFSK_ADC_INPUT);
DIDR0 |= _BV(AFSK_ADC_INPUT); // disable input buffer for ADC pin
ADCSRB = _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0);
ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2); // | _BV(ADPS0);
afsk.decoderStart();
}
AFSK::PacketBuffer::PacketBuffer() {
AX25::PacketBuffer::PacketBuffer() {
nextPacketIn = 0;
nextPacketOut = 0;
inBuffer = 0;
@ -400,7 +322,7 @@ AFSK::PacketBuffer::PacketBuffer() {
#endif
}
unsigned char AFSK::PacketBuffer::readyCount() volatile {
unsigned char AX25::PacketBuffer::readyCount() volatile {
unsigned char i;
unsigned int cnt = 0;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
@ -413,9 +335,9 @@ unsigned char AFSK::PacketBuffer::readyCount() volatile {
}
// Return NULL on empty packet buffers
AFSK::Packet *AFSK::PacketBuffer::getPacket() volatile {
AX25::Packet *AX25::PacketBuffer::getPacket() volatile {
unsigned char i = 0;
AFSK::Packet *p = NULL;
AX25::Packet *p = NULL;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
if(inBuffer == 0) {
@ -438,7 +360,7 @@ AFSK::Packet *AFSK::PacketBuffer::getPacket() volatile {
}
//void Packet::init(uint8_t *buf, unsigned int dlen, bool freeData) {
void AFSK::Packet::init(unsigned short dlen) {
void AX25::Packet::init(unsigned short dlen) {
//data = (unsigned char *)buf;
ready = 0;
#ifdef PACKET_PREALLOCATE
@ -457,8 +379,8 @@ void AFSK::Packet::init(unsigned short dlen) {
}
// Allocate a new packet with a data buffer as set
AFSK::Packet *AFSK::PacketBuffer::makePacket(unsigned short dlen) {
AFSK::Packet *p;
AX25::Packet *AX25::PacketBuffer::makePacket(unsigned short dlen) {
AX25::Packet *p;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
//Packet *p = findPooledPacket();
#ifdef PACKET_PREALLOCATE
@ -475,7 +397,7 @@ AFSK::Packet *AFSK::PacketBuffer::makePacket(unsigned short dlen) {
}
// Free a packet struct, mainly convenience
void AFSK::PacketBuffer::freePacket(Packet *p) {
void AX25::PacketBuffer::freePacket(Packet *p) {
if(!p)
return;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
@ -495,7 +417,7 @@ void AFSK::PacketBuffer::freePacket(Packet *p) {
}
// Put a packet onto the buffer array
bool AFSK::PacketBuffer::putPacket(Packet *p) volatile {
bool AX25::PacketBuffer::putPacket(Packet *p) volatile {
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
if(inBuffer >= PACKET_BUFFER_SIZE) {
return false;
@ -508,11 +430,11 @@ bool AFSK::PacketBuffer::putPacket(Packet *p) volatile {
}
// Print a single byte to the data array
size_t AFSK::Packet::write(uint8_t c) {
size_t AX25::Packet::write(uint8_t c) {
return (appendFCS(c)?1:0);
}
size_t AFSK::Packet::write(const uint8_t *ptr, size_t len) {
size_t AX25::Packet::write(const uint8_t *ptr, size_t len) {
size_t i;
for(i = 0; i < len; ++i)
if(!appendFCS(ptr[i]))
@ -522,7 +444,7 @@ size_t AFSK::Packet::write(const uint8_t *ptr, size_t len) {
// Add a callsign, flagged as source, destination, or digi
// Also tell the routine the SSID to use and if this is the final callsign
size_t AFSK::Packet::appendCallsign(const char *callsign, uint8_t ssid, bool final) {
size_t AX25::Packet::appendCallsign(const char *callsign, uint8_t ssid, bool final) {
uint8_t i;
for(i = 0; i < strlen(callsign) && i < 6; i++) {
appendFCS(callsign[i]<<1);
@ -544,7 +466,7 @@ size_t AFSK::Packet::appendCallsign(const char *callsign, uint8_t ssid, bool fin
#ifdef PACKET_PARSER
// Process the AX25 frame and turn it into a bunch of useful strings
bool AFSK::Packet::parsePacket() {
bool AX25::Packet::parsePacket() {
uint8_t *d = dataPtr;
int i;
@ -619,7 +541,7 @@ bool AFSK::Packet::parsePacket() {
}
#endif
void AFSK::Packet::printPacket(Stream *s) {
void AX25::Packet::printPacket(Stream *s) {
uint8_t i;
#ifdef PACKET_PARSER
if(!parsePacket()) {
@ -722,25 +644,3 @@ void AFSK::Packet::printPacket(Stream *s) {
#endif
}
// Determine what we want to do on this ADC tick.
void AFSK::timer() {
static uint8_t tcnt = 0;
if(++tcnt == T_BIT && encoder.isSending()) {
PORTD |= _BV(6);
// Only run the encoder every 8th tick
// This is actually DDS RefClk / 1200 = 8, set as T_BIT
// A different refclk needs a different value
encoder.process();
tcnt = 0;
PORTD &= ~_BV(6);
} else {
//decoder.process(((int8_t)(ADCH - 128)));
decoder.process((int8_t)(ADCH - 83));
}
}
void AFSK::start(DDS *dds) {
afskEnabled = true;
encoder.setDDS(dds);
decoder.start();
}

285
src/AX25.h Normal file
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@ -0,0 +1,285 @@
#ifndef _AX25_H_
#define _AX25_H_
#include <Arduino.h>
#include <SimpleFIFO.h>
#include <Bell202.h>
#include <avr/pgmspace.h>
#define RX_FIFO_LEN 16
#define AFSK_RX_FIFO_LEN 16
#define PACKET_BUFFER_SIZE 2
#define PACKET_STATIC 0
// Enable the packet parser which will tokenize the AX25 frame into easy strings
#define PACKET_PARSER
// If this is set, all the packet buffers will be pre-allocated at compile time
// This will use more RAM, but can make it easier to do memory planning.
// TODO: Make this actually work right and not crash.
#define PACKET_PREALLOCATE
// This is with all the digis, two addresses, and full payload
// Dst(7) + Src(7) + Digis(56) + Ctl(1) + PID(1) + Data(0-256) + FCS(2)
#define PACKET_MAX_LEN 330
// Minimum is Dst + Src + Ctl + FCS
#define AX25_PACKET_HEADER_MINLEN 17
// HDLC framing bits
#define HDLC_FRAME 0x7E
#define HDLC_RESET 0x7F
#define HDLC_PREAMBLE 0x00
#define HDLC_ESCAPE 0x1B
#define HDLC_TAIL 0x1C
class AX25 {
public:
bool enabled();
void start(DDS *d);
void timer();
class Packet:public Print {
public:
Packet():Print() {};
virtual size_t write(uint8_t);
// Stock virtual method does what we want here.
//virtual size_t write(const char *);
virtual size_t write(const uint8_t *, size_t);
using Print::write;
unsigned char ready : 1;
unsigned char type : 2;
unsigned char freeData : 1;
unsigned short len;
unsigned short maxLen;
//void init(uint8_t *buf, unsigned int dlen, bool freeData);
void init(unsigned short dlen);
inline void free() {
if(freeData)
::free(dataPtr);
}
inline const unsigned char getByte(void) {
return *readPos++;
}
inline const unsigned char getByte(uint16_t p) {
return *(dataPtr+p);
}
inline void start() {
fcs = 0xffff;
// No longer put an explicit frame start here
//*dataPos++ = HDLC_ESCAPE;
//*dataPos++ = HDLC_FRAME;
//len = 2;
len = 0;
}
inline bool append(char c) {
if(len < maxLen) {
++len;
*dataPos++ = c;
return true;
}
return false;
}
#define UPDATE_FCS(d) e=fcs^(d); f=e^(e<<4); fcs=(fcs>>8)^(f<<8)^(f<<3)^(f>>4)
//#define UPDATE_FCS(d) s=(d)^(fcs>>8); t=s^(s>>4); fcs=(fcs<<8)^t^(t<<5)^(t<<12)
inline bool appendFCS(unsigned char c) {
register unsigned char e, f;
if(len < maxLen - 4) { // Leave room for FCS/HDLC
append(c);
UPDATE_FCS(c);
return true;
}
return false;
}
size_t appendCallsign(const char *callsign, uint8_t ssid, bool final = false);
inline void finish() {
append(~(fcs & 0xff));
append(~((fcs>>8) & 0xff));
// No longer append the frame boundaries themselves
//append(HDLC_ESCAPE);
//append(HDLC_FRAME);
ready = 1;
}
inline void clear() {
fcs = 0xffff;
len = 0;
readPos = dataPtr;
dataPos = dataPtr;
}
inline bool crcOK() {
return (fcs == 0xF0B8);
}
#ifdef PACKET_PARSER
bool parsePacket();
#endif
void printPacket(Stream *s);
private:
#ifdef PACKET_PREALLOCATE
uint8_t dataPtr[PACKET_MAX_LEN]; // 256 byte I frame + headers max of 78
#else
uint8_t *dataPtr;
#endif
#ifdef PACKET_PARSER
char srcCallsign[7];
uint8_t srcSSID;
char dstCallsign[7];
uint8_t dstSSID;
char digipeater[8][7];
uint8_t digipeaterSSID[8];
uint8_t *iFrameData;
uint8_t length;
uint8_t control;
uint8_t pid;
#endif
uint8_t *dataPos, *readPos;
unsigned short fcs;
};
class PacketBuffer {
public:
// Initialize the buffers
PacketBuffer();
// How many packets are in the buffer?
unsigned char count() volatile { return inBuffer; };
// And how many of those are ready?
unsigned char readyCount() volatile;
// Retrieve the next packet
Packet *getPacket() volatile;
// Create a packet structure as needed
// This does not place it in the queue
static Packet *makePacket(unsigned short);
// Conveniently free packet memory
static void freePacket(Packet *);
// Place a packet into the buffer
bool putPacket(Packet *) volatile;
private:
volatile unsigned char inBuffer;
Packet * volatile packets[PACKET_BUFFER_SIZE];
volatile unsigned char nextPacketIn;
volatile unsigned char nextPacketOut;
};
class Encoder {
public:
Encoder() {
randomWait = 1000; // At the very begin, wait at least one second
done = true;
packet = 0x0;
currentBytePos = 0;
nextByte = 0;
}
void setDDS(DDS *d) { dds = d; }
//int16 getReferenceClock() { return dds.getReferenceClock(); }
volatile inline bool isDone() volatile {
return done;
}
volatile inline bool hasPackets() volatile {
return (pBuf.count() > 0);
}
inline bool putPacket(Packet *packet) {
return pBuf.putPacket(packet);
}
inline void setRandomWait() {
randomWait = 250 + (rand() % 1000) + millis();
}
bool start();
void stop();
void process();
private:
byte currentByte;
byte currentBit : 1;
byte lastZero : 3;
byte bitPosition : 3;
byte preamble : 6;
//byte bitClock;
bool hdlc;
byte nextByte;
byte maxTx;
Packet *packet;
PacketBuffer pBuf;
unsigned int currentBytePos;
volatile unsigned long randomWait;
volatile bool done;
DDS *dds;
};
class HDLCDecode {
public:
bool hdlcParse(bool, SimpleFIFO<uint8_t,RX_FIFO_LEN> *fifo);
volatile bool rxstart;
private:
uint8_t demod_bits;
uint8_t bit_idx;
uint8_t currchar;
};
class Decoder {
public:
Decoder();
void start();
bool read();
void process(int8_t);
inline bool dataAvailable() {
return (rx_fifo.count() > 0);
}
inline uint8_t getByte() {
return rx_fifo.dequeue();
}
inline uint8_t packetCount() volatile {
return pBuf.count();
}
inline Packet *getPacket() {
return pBuf.getPacket();
}
inline bool isReceiving() volatile {
return hdlc.rxstart;
}
private:
Packet *currentPacket;
SimpleFIFO<uint8_t,RX_FIFO_LEN> rx_fifo; // This should be drained fairly often
PacketBuffer pBuf;
HDLCDecode hdlc;
};
public:
inline bool read() {
return decoder.read();
}
volatile inline bool txReady() volatile {
if(encoder.isDone() && encoder.hasPackets())
return true;
return false;
}
volatile inline bool isDone() volatile { return encoder.isDone(); }
inline bool txStart() {
if(decoder.isReceiving()) {
encoder.setRandomWait();
return false;
}
return encoder.start();
}
inline bool putTXPacket(Packet *packet) {
bool ret = encoder.putPacket(packet);
if(!ret) // No room?
PacketBuffer::freePacket(packet);
return ret;
}
inline Packet *getRXPacket() {
return decoder.getPacket();
}
inline uint8_t rxPacketCount() volatile {
return decoder.packetCount();
}
//unsigned long lastTx;
//unsigned long lastRx;
Encoder encoder;
Decoder decoder;
};
#endif /* _AX25_H_ */

24
src/KISS.cpp
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@ -1,8 +1,8 @@
#include <HamShield.h>
#include "packet.h"
#include "AX25.h"
#include "KISS.h"
//AFSK::Packet kissPacket;
//AX25::Packet kissPacket;
bool inFrame = false;
uint8_t kissBuffer[PACKET_MAX_LEN];
uint16_t kissLen = 0;
@ -11,14 +11,14 @@ uint16_t kissLen = 0;
// KISS equipment, and look if we have anything to relay along
void KISS::loop() {
static bool currentlySending = false;
if(afsk->decoder.read() || afsk->rxPacketCount()) {
if(ax25->decoder.read() || ax25->rxPacketCount()) {
// A true return means something was put onto the packet FIFO
// If we actually have data packets in the buffer, process them all now
while(afsk->rxPacketCount()) {
AFSK::Packet *packet = afsk->getRXPacket();
while(ax25->rxPacketCount()) {
AX25::Packet *packet = ax25->getRXPacket();
if(packet) {
writePacket(packet);
AFSK::PacketBuffer::freePacket(packet);
AX25::PacketBuffer::freePacket(packet);
}
}
}
@ -28,13 +28,13 @@ void KISS::loop() {
if(c == KISS_FEND) {
if(inFrame && kissLen > 0) {
int i;
AFSK::Packet *packet = AFSK::PacketBuffer::makePacket(PACKET_MAX_LEN);
AX25::Packet *packet = AX25::PacketBuffer::makePacket(PACKET_MAX_LEN);
packet->start();
for(i = 0; i < kissLen; i++) {
packet->appendFCS(kissBuffer[i]);
}
packet->finish();
afsk->encoder.putPacket(packet);
ax25->encoder.putPacket(packet);
}
kissLen = 0;
inFrame = false;
@ -57,21 +57,21 @@ void KISS::loop() {
inFrame = true;
}
}
if(afsk->txReady()) {
if(ax25->txReady()) {
radio->setModeTransmit();
currentlySending = true;
if(!afsk->txStart()) { // Unable to start for some reason
if(!ax25->txStart()) { // Unable to start for some reason
radio->setModeReceive();
currentlySending = false;
}
}
if(currentlySending && afsk->encoder.isDone()) {
if(currentlySending && ax25->encoder.isDone()) {
radio->setModeReceive();
currentlySending = false;
}
}
void KISS::writePacket(AFSK::Packet *p) {
void KISS::writePacket(AX25::Packet *p) {
int i;
io->write(KISS_FEND);
io->write((uint8_t)0); // Host to TNC port identifier

8
src/KISS.h
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@ -2,7 +2,7 @@
#define _KISS_H_
#include <HamShield.h>
#include "packet.h"
#include "AX25.h"
#define KISS_FEND 0xC0
#define KISS_FESC 0xDB
@ -11,15 +11,15 @@
class KISS {
public:
KISS(Stream *_io, HamShield *h, DDS *d, AFSK *a) : io(_io), radio(h), dds(d), afsk(a) {}
KISS(Stream *_io, HamShield *h, DDS *d, AX25 *a) : io(_io), radio(h), dds(d), ax25(a) {}
bool read();
void writePacket(AFSK::Packet *);
void writePacket(AX25::Packet *);
void loop();
private:
Stream *io;
HamShield *radio;
DDS *dds;
AFSK *afsk;
AX25 *ax25;
};
#endif /* _KISS_H_ */

132
src/bell202.cpp Normal file
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@ -0,0 +1,132 @@
#include <Arduino.h>
#include "dds.h"
#include "bell202.h"
#define T_BIT ((unsigned int)(SAMPLERATE/BITRATE))
bool Bell202::encoderStart() {
sending = true;
dds->setFrequency(0);
dds->on();
return true;
}
void Bell202::encoderStop() {
sending = false;
dds->setFrequency(0);
dds->off();
}
void Bell202::encoderSetTone(bool tone) {
currentTone = tone;
if(tone == 0) {
PORTD |= _BV(7);
dds->setFrequency(AFSK_SPACE);
} else {
PORTD &= ~_BV(7);
dds->setFrequency(AFSK_MARK);
}
}
template <typename T, int size>
class FastRing {
private:
T ring[size];
uint8_t position;
public:
FastRing(): position(0) {}
inline void write(T value) {
ring[(position++) & (size-1)] = value;
}
inline T read() const {
return ring[position & (size-1)];
}
inline T readn(uint8_t n) const {
return ring[(position + (~n+1)) & (size-1)];
}
};
// Create a delay line that's half the length of the bit cycle (-90 degrees)
FastRing<uint8_t,(T_BIT/2)> delayLine;
// Handle the A/D converter interrupt (hopefully quickly :)
bool Bell202::decoderProcess(int8_t curr_sample) {
// Run the same through the phase multiplier and butterworth filter
iir_x[0] = iir_x[1];
iir_x[1] = ((int8_t)delayLine.read() * curr_sample) >> 2;
iir_y[0] = iir_y[1];
iir_y[1] = iir_x[0] + iir_x[1] + (iir_y[0] >> 1) + (iir_y[0]>>3) + (iir_y[0]>>5);
// Place this ADC sample into the delay line
delayLine.write(curr_sample);
// Shift the bit into place based on the output of the discriminator
sampled_bits <<= 1;
sampled_bits |= (iir_y[1] > 0) ? 1 : 0;
// If we found a 0/1 transition, adjust phases to track
if(EDGE_FOUND(sampled_bits)) {
if(curr_phase < PHASE_THRES)
curr_phase += PHASE_INC;
else
curr_phase -= PHASE_INC;
}
// Move ahead in phase
curr_phase += PHASE_BIT;
// If we've gone over the phase maximum, we should now have some data
if(curr_phase >= PHASE_MAX) {
curr_phase %= PHASE_MAX;
found_bits <<= 1;
// If we have 3 bits or more set, it's a positive bit
register uint8_t bits = sampled_bits & 0x07;
if(bits == 0x07 || bits == 0x06 || bits == 0x05 || bits == 0x03) {
found_bits |= 1;
}
// pass back to encoder
return true;
}
return false;
}
#define AFSK_ADC_INPUT 2
void Bell202::decoderStart() {
/* ASSR &= ~(_BV(EXCLK) | _BV(AS2));
// Do non-inverting PWM on pin OC2B (arduino pin 3) (p.159).
// OC2A (arduino pin 11) stays in normal port operation:
// COM2B1=1, COM2B0=0, COM2A1=0, COM2A0=0
// Mode 1 - Phase correct PWM
TCCR2A = (TCCR2A | _BV(COM2B1)) & ~(_BV(COM2B0) | _BV(COM2A1) | _BV(COM2A0)) |
_BV(WGM21) | _BV(WGM20);
// No prescaler (p.162)
TCCR2B = (TCCR2B & ~(_BV(CS22) | _BV(CS21))) | _BV(CS20) | _BV(WGM22);
OCR2A = pow(2,COMPARE_BITS)-1;
OCR2B = 0;*/
// This lets us use decoding functions that run at the same reference
// clock as the DDS.
// We use ICR1 as TOP and prescale by 8
// Note that this requires the DDS to be started as well
TCCR1A = 0;
TCCR1B = _BV(CS11) | _BV(WGM13) | _BV(WGM12);
ICR1 = ((F_CPU / 8) / 9600) - 1; //TODO: get the actual refclk from dds
// NOTE: should divider be 1 or 8?
ADMUX = _BV(REFS0) | _BV(ADLAR) | AFSK_ADC_INPUT; // Channel AFSK_ADC_INPUT, shift result left (ADCH used)
DDRC &= ~_BV(AFSK_ADC_INPUT);
PORTC &= ~_BV(AFSK_ADC_INPUT);
DIDR0 |= _BV(AFSK_ADC_INPUT); // disable input buffer for ADC pin
ADCSRB = _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0);
ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2); // | _BV(ADPS0);
}
void Bell202::start(DDS *dds) {
afskEnabled = true;
encoderSetDDS(dds);
decoderStart();
}

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src/bell202.h Normal file
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#ifndef _BELL202_H_
#define _BELL202_H_
/*
* bell202.h
* The Bell202 class implements an AFSK transceiver at the bit level.
* All encoding and framing should be done at a higher level (e.g. HDLC and AX.25)
*
* See http://destevez.net/2016/06/kiss-hdlc-ax-25-and-friends/
*/
#include <Arduino.h>
#include <DDS.h>
#include <avr/pgmspace.h>
#define SAMPLERATE 9600
#define BITRATE 1200
#define SAMPLEPERBIT (SAMPLERATE / BITRATE)
#define RX_FIFO_LEN 16
#define AFSK_RX_FIFO_LEN 16
#define BIT_DIFFER(bitline1, bitline2) (((bitline1) ^ (bitline2)) & 0x01)
#define EDGE_FOUND(bitline) BIT_DIFFER((bitline), (bitline) >> 1)
#define T_BIT ((unsigned int)(SAMPLERATE/BITRATE))
#define PHASE_BIT 8
#define PHASE_INC 1
#define PHASE_MAX (SAMPLEPERBIT * PHASE_BIT)
#define PHASE_THRES (PHASE_MAX / 2)
#define AFSK_SPACE 2200
#define AFSK_MARK 1200
#define ADC_OFFSET 83
class Bell202 {
private:
volatile bool afskEnabled;
public:
Bell202() {
sending = false;
}
volatile inline bool enabled() { return afskEnabled; }
volatile inline bool isSending() volatile {
return sending;
}
void encoderSetDDS(DDS *d) { dds = d; }
//int16 getReferenceClock() { return dds.getReferenceClock(); }
bool encoderStart();
void encoderStop();
void encoderSetTone(bool tone);
bool encoderGetTone() { return currentTone; }
void decoderStart();
bool decoderRead();
bool decoderProcess(int8_t);
void start(DDS *);
uint8_t found_bits;
private:
volatile bool sending;
byte currentTone : 1;
//byte bitClock;
DDS *dds;
int16_t iir_x[2];
int16_t iir_y[2];
int8_t curr_phase;
uint8_t sampled_bits;
};
#endif /* _BELL202_H_ */

307
src/packet.h
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#ifndef _AFSK_H_
#define _AFSK_H_
#ifndef _PACKET_H_
#define _PACKET_H_
#include <Arduino.h>
#include <SimpleFIFO.h>
#include <DDS.h>
#include <avr/pgmspace.h>
#include "AX25.h"
#include "bell202.h"
#define SAMPLERATE 9600
#define BITRATE 1200
#define AFSK AX25 //
#define SAMPLEPERBIT (SAMPLERATE / BITRATE)
#define RX_FIFO_LEN 16
#define AFSK_RX_FIFO_LEN 16
#define PACKET_BUFFER_SIZE 2
#define PACKET_STATIC 0
// Enable the packet parser which will tokenize the AX25 frame into easy strings
#define PACKET_PARSER
// If this is set, all the packet buffers will be pre-allocated at compile time
// This will use more RAM, but can make it easier to do memory planning.
// TODO: Make this actually work right and not crash.
#define PACKET_PREALLOCATE
// This is with all the digis, two addresses, and full payload
// Dst(7) + Src(7) + Digis(56) + Ctl(1) + PID(1) + Data(0-256) + FCS(2)
#define PACKET_MAX_LEN 330
// Minimum is Dst + Src + Ctl + FCS
#define AX25_PACKET_HEADER_MINLEN 17
// HDLC framing bits
#define HDLC_FRAME 0x7E
#define HDLC_RESET 0x7F
#define HDLC_PREAMBLE 0x00
#define HDLC_ESCAPE 0x1B
#define HDLC_TAIL 0x1C
class AFSK {
private:
volatile bool afskEnabled;
public:
bool enabled() { return afskEnabled; };
class Packet:public Print {
public:
Packet():Print() {};
virtual size_t write(uint8_t);
// Stock virtual method does what we want here.
//virtual size_t write(const char *);
virtual size_t write(const uint8_t *, size_t);
using Print::write;
unsigned char ready : 1;
unsigned char type : 2;
unsigned char freeData : 1;
unsigned short len;
unsigned short maxLen;
//void init(uint8_t *buf, unsigned int dlen, bool freeData);
void init(unsigned short dlen);
inline void free() {
if(freeData)
::free(dataPtr);
}
inline const unsigned char getByte(void) {
return *readPos++;
}
inline const unsigned char getByte(uint16_t p) {
return *(dataPtr+p);
}
inline void start() {
fcs = 0xffff;
// No longer put an explicit frame start here
//*dataPos++ = HDLC_ESCAPE;
//*dataPos++ = HDLC_FRAME;
//len = 2;
len = 0;
}
inline bool append(char c) {
if(len < maxLen) {
++len;
*dataPos++ = c;
return true;
}
return false;
}
#define UPDATE_FCS(d) e=fcs^(d); f=e^(e<<4); fcs=(fcs>>8)^(f<<8)^(f<<3)^(f>>4)
//#define UPDATE_FCS(d) s=(d)^(fcs>>8); t=s^(s>>4); fcs=(fcs<<8)^t^(t<<5)^(t<<12)
inline bool appendFCS(unsigned char c) {
register unsigned char e, f;
if(len < maxLen - 4) { // Leave room for FCS/HDLC
append(c);
UPDATE_FCS(c);
return true;
}
return false;
}
size_t appendCallsign(const char *callsign, uint8_t ssid, bool final = false);
inline void finish() {
append(~(fcs & 0xff));
append(~((fcs>>8) & 0xff));
// No longer append the frame boundaries themselves
//append(HDLC_ESCAPE);
//append(HDLC_FRAME);
ready = 1;
}
inline void clear() {
fcs = 0xffff;
len = 0;
readPos = dataPtr;
dataPos = dataPtr;
}
inline bool crcOK() {
return (fcs == 0xF0B8);
}
#ifdef PACKET_PARSER
bool parsePacket();
#endif
void printPacket(Stream *s);
private:
#ifdef PACKET_PREALLOCATE
uint8_t dataPtr[PACKET_MAX_LEN]; // 256 byte I frame + headers max of 78
#else
uint8_t *dataPtr;
#endif
#ifdef PACKET_PARSER
char srcCallsign[7];
uint8_t srcSSID;
char dstCallsign[7];
uint8_t dstSSID;
char digipeater[8][7];
uint8_t digipeaterSSID[8];
uint8_t *iFrameData;
uint8_t length;
uint8_t control;
uint8_t pid;
#endif
uint8_t *dataPos, *readPos;
unsigned short fcs;
};
class PacketBuffer {
public:
// Initialize the buffers
PacketBuffer();
// How many packets are in the buffer?
unsigned char count() volatile { return inBuffer; };
// And how many of those are ready?
unsigned char readyCount() volatile;
// Retrieve the next packet
Packet *getPacket() volatile;
// Create a packet structure as needed
// This does not place it in the queue
static Packet *makePacket(unsigned short);
// Conveniently free packet memory
static void freePacket(Packet *);
// Place a packet into the buffer
bool putPacket(Packet *) volatile;
private:
volatile unsigned char inBuffer;
Packet * volatile packets[PACKET_BUFFER_SIZE];
volatile unsigned char nextPacketIn;
volatile unsigned char nextPacketOut;
};
class Encoder {
public:
Encoder() {
randomWait = 1000; // At the very begin, wait at least one second
sending = false;
done = true;
packet = 0x0;
currentBytePos = 0;
nextByte = 0;
}
void setDDS(DDS *d) { dds = d; }
//int16 getReferenceClock() { return dds.getReferenceClock(); }
volatile inline bool isSending() volatile {
return sending;
}
volatile inline bool isDone() volatile {
return done;
}
volatile inline bool hasPackets() volatile {
return (pBuf.count() > 0);
}
inline bool putPacket(Packet *packet) {
return pBuf.putPacket(packet);
}
inline void setRandomWait() {
randomWait = 250 + (rand() % 1000) + millis();
}
bool start();
void stop();
void process();
private:
volatile bool sending;
byte currentByte;
byte currentBit : 1;
byte currentTone : 1;
byte lastZero : 3;
byte bitPosition : 3;
byte preamble : 6;
//byte bitClock;
bool hdlc;
byte nextByte;
byte maxTx;
Packet *packet;
PacketBuffer pBuf;
unsigned int currentBytePos;
volatile unsigned long randomWait;
volatile bool done;
DDS *dds;
};
class HDLCDecode {
public:
bool hdlcParse(bool, SimpleFIFO<uint8_t,RX_FIFO_LEN> *fifo);
volatile bool rxstart;
private:
uint8_t demod_bits;
uint8_t bit_idx;
uint8_t currchar;
};
class Decoder {
public:
Decoder();
void start();
bool read();
void process(int8_t);
inline bool dataAvailable() {
return (rx_fifo.count() > 0);
}
inline uint8_t getByte() {
return rx_fifo.dequeue();
}
inline uint8_t packetCount() volatile {
return pBuf.count();
}
inline Packet *getPacket() {
return pBuf.getPacket();
}
inline bool isReceiving() volatile {
return hdlc.rxstart;
}
private:
Packet *currentPacket;
//SimpleFIFO<int8_t,SAMPLEPERBIT/2+1> delay_fifo;
SimpleFIFO<uint8_t,RX_FIFO_LEN> rx_fifo; // This should be drained fairly often
int16_t iir_x[2];
int16_t iir_y[2];
uint8_t sampled_bits;
int8_t curr_phase;
uint8_t found_bits;
PacketBuffer pBuf;
HDLCDecode hdlc;
};
public:
inline bool read() {
return decoder.read();
}
volatile inline bool txReady() volatile {
if(encoder.isDone() && encoder.hasPackets())
return true;
return false;
}
volatile inline bool isDone() volatile { return encoder.isDone(); }
inline bool txStart() {
if(decoder.isReceiving()) {
encoder.setRandomWait();
return false;
}
return encoder.start();
}
inline bool putTXPacket(Packet *packet) {
bool ret = encoder.putPacket(packet);
if(!ret) // No room?
PacketBuffer::freePacket(packet);
return ret;
}
inline Packet *getRXPacket() {
return decoder.getPacket();
}
inline uint8_t rxPacketCount() volatile {
return decoder.packetCount();
}
//unsigned long lastTx;
//unsigned long lastRx;
void start(DDS *);
void timer();
Encoder encoder;
Decoder decoder;
};
#endif /* _AFSK_H_ */
#endif /* _PACKET_H_ */