v2

Inc/ax25.h

@@ -31,7 +31,6 @@ enum Ax25RxStage
 	RX_STAGE_FLAG,
 	RX_STAGE_FRAME,
 #ifdef ENABLE_FX25
-	RX_STAGE_FX25_TAG,
 	RX_STAGE_FX25_FRAME,
 #endif
 };

Src/ax25.c

@@ -135,7 +135,6 @@ struct RxState
 #ifdef ENABLE_FX25
 	struct Fx25Mode *fx25Mode;
 	uint64_t tag; //received correlation tag
-	uint8_t tagBit;
 #endif
 };
 
@@ -537,42 +536,20 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 	rx->tag >>= 1;
 	if(bit)
 		rx->tag |= 0x8000000000000000;
-	rx->tagBit++;
 
-
-	if((rx->rx == RX_STAGE_FX25_TAG) || (rx->rx == RX_STAGE_FX25_FRAME))
+	if(Ax25Config.fx25
+			&& (rx->rx != RX_STAGE_FX25_FRAME)
+			&& (NULL != (rx->fx25Mode = (struct Fx25Mode*)Fx25GetModeForTag(rx->tag))))
 	{
-		if((rx->rx == RX_STAGE_FX25_TAG) && (rx->tagBit == 64))
-		{
-			if(Ax25Config.fx25)
-			{
-				rx->fx25Mode = (struct Fx25Mode*)Fx25GetModeForTag(rx->tag);
-				if(Ax25Config.fx25 && (rx->fx25Mode != NULL))
-				{
-					rx->rx = RX_STAGE_FX25_FRAME;
-					rx->frameIdx = 0;
-					rx->receivedBitIdx = 0;
-					rx->receivedByte = 0;
-					return;
-				}
-			}
-			rx->rx = RX_STAGE_FRAME;
-		}
+		rx->rx = RX_STAGE_FX25_FRAME;
+		rx->receivedByte = 0;
+		rx->receivedBitIdx = 0;
+		rx->frameIdx = 0;
+		return;
 	}
-	else
+
+	if(rx->rx != RX_STAGE_FX25_FRAME)
 	{
-			if(rx->rawData != 0x7E)
-			{
-				if(Ax25Config.fx25)
-				{
-					if((rx->rx == RX_STAGE_FLAG) && (rx->tagBit == 8))
-						rx->rx = RX_STAGE_FX25_TAG;
-				}
-				else
-					rx->rx = RX_STAGE_FRAME;
-			}
-			else
-				rx->tagBit = 0;
 #endif
 
 		if(rx->rawData == 0x7E) //HDLC flag received
@@ -638,12 +615,14 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 			rx->frameIdx = 0;
 			return;
 		}
+		else
+			rx->rx = RX_STAGE_FRAME;
 
 #ifdef ENABLE_FX25
 	}
 
 
-	if((rx->rx != RX_STAGE_FX25_FRAME) && (rx->rx != RX_STAGE_FX25_TAG))
+	if(rx->rx != RX_STAGE_FX25_FRAME)
 	{
 #else
 	{
@@ -689,8 +668,7 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 					h->corrected = AX25_NOT_FX25;
 				lastCrc = crc;
 			}
-			rx->rx = RX_STAGE_FX25_TAG;
-			rx->tagBit = 0;
+			rx->rx = RX_STAGE_FLAG;
 			rx->receivedByte = 0;
 			rx->receivedBitIdx = 0;
 			rx->frameIdx = 0;

Src/drivers/modem.c

@@ -70,7 +70,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #define AMP_TRACKING_DECAY 0.00004f //0.00004
 
 
-#define DAC_SINE_SIZE 32 //DAC sine table size
+#define DAC_SINE_SIZE 128 //DAC sine table size
 
 
 struct ModemDemodConfig ModemConfig;
@@ -347,7 +347,7 @@ void DMA1_Channel2_IRQHandler(void)
  	if(ModemConfig.modem == MODEM_9600)
  	{
  		if(ModemConfig.usePWM)
- 			sample = scrambledSymbol ? 99 : 0;
+ 			sample = scrambledSymbol ? 256 : 1;
  		else
  			sample = scrambledSymbol ? 15 : 0;
 
@@ -367,7 +367,7 @@ void DMA1_Channel2_IRQHandler(void)
  	else
  	{
  		GPIOB->ODR &= ~0xF000; //zero 4 oldest bits
- 		GPIOB->ODR |= (sample << 12); //write sample to 4 oldest bits
+ 		GPIOB->ODR |= ((uint32_t)sample << 12); //write sample to 4 oldest bits
  	}
 
 }
@@ -434,11 +434,11 @@ static int32_t demodulate(int16_t sample, struct DemodState *dem)
 
 	if(sample <= dem->valley)
 	{
-		dem->valley += (((int32_t)(AMP_TRACKING_ATTACK * (float)32768) * (int32_t)(sample - dem->valley)) >> 15);
+		dem->valley -= (((int32_t)(AMP_TRACKING_ATTACK * (float)32768) * (int32_t)(dem->valley - sample)) >> 15);
 	}
 	else
 	{
-		dem->valley += (((int32_t)(AMP_TRACKING_DECAY * (float)32768) * (int32_t)(sample - dem->valley)) >> 15);
+		dem->valley -= (((int32_t)(AMP_TRACKING_DECAY * (float)32768) * (int32_t)(dem->valley - sample)) >> 15);
 	}
 
 
@@ -492,7 +492,7 @@ static int32_t demodulate(int16_t sample, struct DemodState *dem)
 
 	if((sample > 0) != dem->dcdLastSymbol) //tone changed
 	{
-		if(abs(dem->dcdPll) <= (uint32_t)(dem->pllStep)) //tone change occurred near zero
+		if((uint32_t)abs(dem->dcdPll) <= (uint32_t)(dem->pllStep)) //tone change occurred near zero
 			dem->dcdCounter += dem->dcdInc; //increase DCD counter
 		else //tone change occurred far from zero
 		{
@@ -943,7 +943,8 @@ void ModemInit(void)
 	for(uint8_t i = 0; i < DAC_SINE_SIZE; i++) //calculate DAC sine samples
 	{
 		if(ModemConfig.usePWM)
-			dacSine[i] = ((sinf(2.f * 3.1416f * (float)i / (float)DAC_SINE_SIZE) + 1.f) * 45.f);
+			//produce values in range 1 to 256
+			dacSine[i] = ((sinf(2.f * 3.1416f * (float)i / (float)DAC_SINE_SIZE) + 1.f) * 128.f);
 		else
 			dacSine[i] = ((7.f * sinf(2.f * 3.1416f * (float)i / (float)DAC_SINE_SIZE)) + 8.f);
 	}
@@ -957,12 +958,12 @@ void ModemInit(void)
 		 GPIOB->CRL &= ~GPIO_CRL_CNF6_0;
 
 		 //set up PWM generation
-		 TIM4->PSC = 7; //72MHz/8=9MHz
-		 TIM4->ARR = 90; //9MHz/90=100kHz
+		 TIM4->PSC = 2; //72MHz/3=24MHz
+		 TIM4->ARR = 257; //18MHz/258=93kHz
 
 		 TIM4->CCMR1 |= TIM_CCMR1_OC1M_1 | TIM_CCMR1_OC1M_2;
 		 TIM4->CCER |= TIM_CCER_CC1E;
-		 TIM4->CCR1 = 44; //initial duty cycle
+		 TIM4->CCR1 = 127; //initial duty cycle
 
 		 TIM4->CR1 |= TIM_CR1_CEN;
 	}

Src/fx25.c

@@ -25,13 +25,13 @@ const struct Fx25Mode Fx25ModeList[11] =
 	{.tag =  0x4A4ABEC4A724B796, .K = 64, .T = 64}
 };
 
-static inline uint8_t hammingDistance(uint64_t x, uint64_t y)
+static uint8_t hammingDistance(uint64_t x, uint64_t y)
 {
 	x ^= y;
 	uint8_t distance = 0;
 	for(uint8_t i = 0; i < 64; i++)
 	{
-		distance += (x & 1) > 0;
+		distance += (x & 1);
 		x >>= 1;
 	}
 	return distance;

Src/main.c

@@ -136,7 +136,7 @@ static void handleFrame(void)
 							TermSendToAll(MODE_MONITOR, (uint8_t*)"F", 1);
 							break;
 						case PREFILTER_NONE:
-							TermSendToAll(MODE_MONITOR, (uint8_t*)"*", 1);
+							TermSendToAll(MODE_MONITOR, (uint8_t*)"N", 1);
 					}
 				}
 				else
@@ -224,7 +224,7 @@ int main(void)
 	//set some initial values in case there is no configuration saved in memory
 	Uart1.baudrate = 9600;
 	Uart2.baudrate = 9600;
-	ModemConfig.usePWM = 0;
+	ModemConfig.usePWM = 1;
 	ModemConfig.flatAudioIn = 0;
 	Ax25Config.quietTime = 300;
 	Ax25Config.txDelayLength = 300;