modem frequency correction

CHANGELOG.md

@@ -1,3 +1,41 @@
+# 2.0.0 (2023-09-05)
+## New features
+* New modems: AFSK Bell 103 (300 Bd, 1600/1800 Hz), GFSK G3RUH (9600 Bd), AFSK V.23 (1200 Bd, 1300/2100 Hz)
+* FX.25 (AX.25 with Reed-Solomon FEC) support
+## Bug fixes
+* none
+## Other
+* New signal level measurement method
+## Known bugs
+* none
+# 1.3.3 (2023-09-04)
+## New features
+* none
+## Bug fixes
+* RX buffer pointers bug fix
+* AX.25 to TNC2 converter bug with non-UI frames
+## Other
+* New KISS handling method to support long and multiple frames
+## Known bugs
+* none
+# 1.3.2 (2023-08-31)
+## New features
+* none
+## Bug fixes
+* Duplicate protection was not working properly
+## Other
+* none
+## Known bugs
+* none
+# 1.3.1 (2023-08-30)
+## New features
+* none
+## Bug fixes
+* Non-APRS switch was not stored in memory
+## Other
+* PWM is now the default option
+## Known bugs
+* none
 # 1.3.0 (2023-08-30)
 ## New features
 * Callsign is now set together with SSID using ```call <call-SSID>```

Inc/ax25.h

@@ -25,6 +25,17 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 
 #define AX25_NOT_FX25 255
 
+#ifndef ENABLE_FX25
+//for AX.25 308 bytes is the theoretical max size assuming 2-byte Control, 256-byte info field and 5 digi address fields
+#define AX25_FRAME_MAX_SIZE (308) //single frame max length
+#else
+//in FX.25 mode the block can be 255 bytes long at most, and the AX.25 frame itself must be even smaller
+//frames that are too long are sent as standard AX.25 frames
+//Reed-Solomon library needs a bit of memory and the frame buffer must be smaller
+//otherwise we run out of RAM
+#define AX25_FRAME_MAX_SIZE (265) //single frame max length
+#endif
+
 enum Ax25RxStage
 {
 	RX_STAGE_IDLE = 0,
@@ -47,12 +58,6 @@ struct Ax25ProtoConfig
 
 extern struct Ax25ProtoConfig Ax25Config;
 
-/**
- * @brief Transmit one or more frames encoded in KISS format
- * @param *buf Inout buffer
- * @param len Buffer size
- */
-void Ax25TxKiss(uint8_t *buf, uint16_t len);
 
 /**
  * @brief Write frame to transmit buffer

Inc/drivers/uart.h

@@ -23,7 +23,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include "usbd_cdc_if.h"
 #include "ax25.h"
 
-#define UART_BUFFER_SIZE 250
+#define UART_BUFFER_SIZE 130
 
 enum UartMode
 {
@@ -35,7 +35,6 @@ enum UartMode
 enum UartDataType
 {
 	DATA_NOTHING = 0,
-	DATA_KISS,
 	DATA_TERM,
 	DATA_USB,
 };
@@ -53,20 +52,14 @@ typedef struct
 	uint16_t txBufferHead, txBufferTail;
 	uint8_t txBufferFull : 1;
 	enum UartMode mode;
-	uint32_t kissTimer;
 	uint16_t lastRxBufferHead; //for special characters handling
+	uint8_t kissBuffer[AX25_FRAME_MAX_SIZE + 1];
+	uint16_t kissBufferHead;
 } Uart;
 
 extern Uart Uart1, Uart2, UartUsb;
 
 
-///**
-// * \brief Copy KISS frame(s) from input buffer to APRS TX buffer
-// * \param[in] *buf Input buffer
-// * \param[in] len Input buffer size
-// */
-//uint8_t Uart_txKiss(uint8_t *buf, uint16_t len);
-
 /**
  * @brief Send byte
  * @param[in] *port UART
@@ -111,11 +104,4 @@ void UartConfig(Uart *port, uint8_t state);
  */
 void UartClearRx(Uart *port);
 
-/**
- * @brief Handle KISS timeout
- * @param *port UART pointer
- * @attention This function must be polled constantly in main loop for USB UART.
- */
-void UartHandleKissTimeout(Uart *port);
-
 #endif

Inc/kiss.h

@@ -0,0 +1,41 @@
+/*
+Copyright 2020-2023 Piotr Wilkon
+
+This file is part of VP-Digi.
+
+VP-Digi is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+VP-Digi is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef KISS_H_
+#define KISS_H_
+
+#include <stdint.h>
+#include "drivers/uart.h"
+
+/**
+ * @brief Convert AX.25 frame to KISS and send
+ * @param *port UART structure
+ * @param *buf Frame buffer
+ * @param size Frame size
+ */
+void KissSend(Uart *port, uint8_t *buf, uint16_t size);
+
+/**
+ * @brief Parse bytes received from UART to form a KISS frame (possibly) and send this frame
+ * @param *port UART structure
+ * @param data Received byte
+ */
+void KissParse(Uart *port, uint8_t data);
+
+#endif /* KISS_H_ */

Src/ax25.c

@@ -29,21 +29,12 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 
 struct Ax25ProtoConfig Ax25Config;
 
-//values below must be kept consistent so that FRAME_BUFFER_SIZE >= FRAME_MAX_SIZE * FRAME_MAX_COUNT
-#ifndef ENABLE_FX25
-//for AX.25 308 bytes is the theoretical max size assuming 2-byte Control, 256-byte info field and 5 digi address fields
-#define FRAME_MAX_SIZE (308) //single frame max length
-#else
-//in FX.25 mode the block can be 255 bytes long at most, and the AX.25 frame itself must be even smaller
-//frames that are too long are sent as standard AX.25 frames
-//Reed-Solomon library needs a bit of memory and the frame buffer must be smaller
-//otherwise we run out of RAM
-#define FRAME_MAX_SIZE (265) //single frame max length
+#ifdef ENABLE_FX25
 #include "fx25.h"
 #endif
 
 #define FRAME_MAX_COUNT (10) //max count of frames in buffer
-#define FRAME_BUFFER_SIZE (FRAME_MAX_COUNT * FRAME_MAX_SIZE) //circular frame buffer length
+#define FRAME_BUFFER_SIZE (FRAME_MAX_COUNT * AX25_FRAME_MAX_SIZE) //circular frame buffer length
 
 #define STATIC_HEADER_FLAG_COUNT 4 //number of flags sent before each frame
 #define STATIC_FOOTER_FLAG_COUNT 8 //number of flags sent after each frame
@@ -126,7 +117,7 @@ static enum TxStage txStage; //current TX stage
 struct RxState
 {
 	uint16_t crc; //current CRC
-	uint8_t frame[FRAME_MAX_SIZE]; //raw frame buffer
+	uint8_t frame[AX25_FRAME_MAX_SIZE]; //raw frame buffer
 	uint16_t frameIdx; //index for raw frame buffer
 	uint8_t receivedByte; //byte being currently received
 	uint8_t receivedBitIdx; //bit index for recByte
@@ -147,7 +138,7 @@ static uint16_t rxMultiplexDelay = 0; //simple delay for decoder multiplexer to
 static uint16_t txDelay; //number of TXDelay bytes to send
 static uint16_t txTail; //number of TXTail bytes to send
 
-static uint8_t outputFrameBuffer[FRAME_MAX_SIZE];
+static uint8_t outputFrameBuffer[AX25_FRAME_MAX_SIZE];
 
 #define GET_FREE_SIZE(max, head, tail) (((head) < (tail)) ? ((tail) - (head)) : ((max) - (head) + (tail)))
 #define GET_USED_SIZE(max, head, tail) (max - GET_FREE_SIZE(max, head, tail))
@@ -178,31 +169,6 @@ void Ax25ClearReceivedFrameBitmap(void)
 	frameReceived = 0;
 }
 
-void Ax25TxKiss(uint8_t *buf, uint16_t len)
-{
-	if(len < 18) //frame is too small
-	{
-		return;
-	}
-	for(uint16_t i = 0; i < len; i++)
-	{
-		if(buf[i] == 0xC0) //frame start marker
-		{
-			uint16_t end = i + 1;
-			while(end < len)
-			{
-				if(buf[end] == 0xC0)
-					break;
-				end++;
-			}
-			if(end == len) //no frame end marker found
-				return;
-			Ax25WriteTxFrame(&buf[i + 2], end - (i + 2)); //skip modem number and send frame
-			DigiStoreDeDupe(&buf[i + 2], end - (i + 2));
-			i = end; //move pointer to the next byte if there are more consecutive frames
-		}
-	}
-}
 
 static void removeLastFrameFromRxBuffer(void)
 {
@@ -435,9 +401,6 @@ endParseFx25Frame:
 
 void *Ax25WriteTxFrame(uint8_t *data, uint16_t size)
 {
-	while(txStage != TX_STAGE_IDLE)
-		;
-
 	if(txFrameBufferFull)
 		return NULL;
 
@@ -471,10 +434,12 @@ void *Ax25WriteTxFrame(uint8_t *data, uint16_t size)
 
 
 	void *ret = &txFrame[txFrameHead];
+	__disable_irq();
 	txFrameHead++;
 	txFrameHead %= FRAME_MAX_COUNT;
 	if(txFrameHead == txFrameTail)
 		txFrameBufferFull = true;
+	__enable_irq();
 	return ret;
 }
 
@@ -497,10 +462,11 @@ bool Ax25ReadNextRxFrame(uint8_t **dst, uint16_t *size, int8_t *peak, int8_t *va
 	*size = rxFrame[rxFrameTail].size;
 	*corrected = rxFrame[rxFrameTail].corrected;
 
+	__disable_irq();
 	rxFrameBufferFull = false;
-
 	rxFrameTail++;
 	rxFrameTail %= FRAME_MAX_COUNT;
+	__enable_irq();
 	return true;
 }
 
@@ -594,10 +560,12 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 									rxFrame[rxFrameHead].fx25Mode = NULL;
 #endif
 									rxFrame[rxFrameHead].corrected = AX25_NOT_FX25;
+									__disable_irq();
 									rxFrame[rxFrameHead++].size = rx->frameIdx;
 									rxFrameHead %= FRAME_MAX_COUNT;
-									if(rxFrameHead == txFrameHead)
+									if(rxFrameHead == rxFrameTail)
 										rxFrameBufferFull = true;
+									__enable_irq();
 
 									for(uint16_t i = 0; i < rx->frameIdx; i++)
 									{
@@ -629,7 +597,7 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 	{
 		//this condition must not be checked when FX.25 is enabled
 		//because FX.25 parity bytes and tags contain >= 7 consecutive ones
-		if((rx->rawData & 0x7F) == 0x7F) //received 7 consecutive ones, this is an error (sometimes called "escape byte")
+		if((rx->rawData & 0x7F) == 0x7F) //received 7 consecutive ones, this is an error
 		{
 			rx->rx = RX_STAGE_FLAG;
 			rx->receivedByte = 0;
@@ -678,7 +646,7 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 #else
 		rx->rx = RX_STAGE_FRAME;
 #endif
-		if(rx->frameIdx >= FRAME_MAX_SIZE) //frame is too long
+		if(rx->frameIdx >= AX25_FRAME_MAX_SIZE) //frame is too long
 		{
 			rx->rx = RX_STAGE_IDLE;
 			rx->receivedByte = 0;
@@ -750,8 +718,10 @@ transmitTag:
 		if(txStage == TX_STAGE_DATA) //transmitting normal data
 		{
 transmitNormalData:
+			__disable_irq();
 			if((txFrameHead != txFrameTail) || txFrameBufferFull)
 			{
+				__enable_irq();
 				if(txByteIdx < txFrame[txFrameTail].size) //send buffer
 				{
 					txByte = txBuffer[(txFrame[txFrameTail].start + txByteIdx) % FRAME_BUFFER_SIZE];
@@ -760,10 +730,12 @@ transmitNormalData:
 #ifdef ENABLE_FX25
 				else if(txFrame[txFrameTail].fx25Mode != NULL)
 				{
+					__disable_irq();
 					txFrameBufferFull = false;
 					txFrameTail++;
 					txFrameTail %= FRAME_MAX_COUNT;
 					txByteIdx = 0;
+					__enable_irq();
 					if((txFrameHead != txFrameTail) || txFrameBufferFull)
 					{
 						if(txFrame[txFrameTail].fx25Mode != NULL)
@@ -788,6 +760,7 @@ transmitNormalData:
 			else //no more frames
 			{
 transmitTail:
+				__enable_irq();
 				txByteIdx = 0;
 				txBitIdx = 0;
 				txStage = TX_STAGE_TAIL;
@@ -819,6 +792,7 @@ transmitTail:
 			else
 			{
 				txFlagsElapsed = 0;
+				__disable_irq();
 				txFrameBufferFull = false;
 				txFrameTail++;
 				txFrameTail %= FRAME_MAX_COUNT;
@@ -826,11 +800,13 @@ transmitTail:
 #ifdef ENABLE_FX25
 				if(((txFrameHead != txFrameTail) || txFrameBufferFull) && (txFrame[txFrameTail].fx25Mode != NULL))
 				{
+					__enable_irq();
 					txStage = TX_STAGE_CORRELATION_TAG;
 					txTagByteIdx = 0;
 					goto transmitTag;
 				}
 #endif
+				__enable_irq();
 				txStage = TX_STAGE_DATA; //return to normal data transmission stage. There might be a next frame to transmit
 				goto transmitNormalData;
 			}

Src/common.c

@@ -148,11 +148,16 @@ static void sendTNC2ToUart(Uart *uart, uint8_t *from, uint16_t len)
 
     }
 
-    UartSendByte(uart, ':'); //separator
+	UartSendByte(uart, ':'); //separator
 
-    nextPathEl += 2; //skip Control and PID
+    if((from[nextPathEl] & 0b11101111) == 0b00000011) //check if UI packet
+    {
+		nextPathEl += 2; //skip Control and PID
 
-    UartSendString(uart, &(from[nextPathEl]), len - nextPathEl); //send information field
+		UartSendString(uart, &(from[nextPathEl]), len - nextPathEl); //send information field
+    }
+    else
+    	UartSendString(uart, "<not UI packet>", 0);
 
     UartSendByte(uart, 0); //terminate with NULL
 }

Src/digipeater.c

@@ -50,8 +50,7 @@ static struct DeDupeData deDupe[DEDUPE_SIZE]; //duplicate protection hash buffer
 static uint8_t deDupeCount = 0; //duplicate protection buffer index
 
 
-#define DIGI_BUFFER_SIZE 308 //308 is the theoretical max under some assumptions, see ax25.c
-static uint8_t buf[DIGI_BUFFER_SIZE];
+static uint8_t buf[AX25_FRAME_MAX_SIZE];
 
 /**
  * @brief Check if frame with specified hash is already in viscous-delay buffer and delete it if so
@@ -198,7 +197,7 @@ static void makeFrame(uint8_t *frame, uint16_t elStart, uint16_t len, uint32_t h
     }
     else //normal mode
     {
-    	if((uint32_t)sizeof(buf) < (len + 7))
+    	if((uint16_t)sizeof(buf) < (len + 7))
     		return;
     	buffer = buf;
     }

Src/drivers/modem.c

@@ -593,7 +593,7 @@ void ModemTxTestStart(enum ModemTxTestMode type)
 
 	 if(ModemConfig.modem == MODEM_9600)
 	 {
-		TIM1->ARR = 103;
+		TIM1->ARR = markStep;
 		//enable baudrate generator
 		TIM3->CR1 = TIM_CR1_CEN; //enable timer
 		NVIC_EnableIRQ(TIM3_IRQn); //enable interrupt in NVIC
@@ -637,7 +637,7 @@ void ModemTransmitStart(void)
 {
 	 setPtt(1); //PTT on
 	 if(ModemConfig.modem == MODEM_9600)
-		 TIM1->ARR = 103;
+		 TIM1->ARR = markStep;
 
 	 TIM3->CR1 = TIM_CR1_CEN;
 	 TIM1->CR1 = TIM_CR1_CEN;
@@ -688,8 +688,8 @@ void ModemInit(void)
 	memset(demodState, 0, sizeof(demodState));
 
 	/**
-	 * TIM1 is used for pushing samples to DAC (R2R or PWM) (clocked at 4 MHz)
-	 * TIM3 is the baudrate generator for TX (clocked at 1 MHz)
+	 * TIM1 is used for pushing samples to DAC (R2R or PWM) (clocked at 18 MHz)
+	 * TIM3 is the baudrate generator for TX (clocked at 18 MHz)
 	 * TIM4 is the PWM generator with no software interrupt
 	 * TIM2 is the RX sampling timer with no software interrupt, but it directly calls DMA
 	 */
@@ -764,11 +764,11 @@ void ModemInit(void)
 	 TIM2->DIER |= TIM_DIER_UDE; //enable calling DMA on timer tick
 
 	 //TX DAC timer
-	 TIM1->PSC = 17; //72/18=4 MHz
+	 TIM1->PSC = 3; //72/4=18 MHz
 	 TIM1->DIER |= TIM_DIER_UIE;
 
 	 //baudrate timer
-	 TIM3->PSC = 3; //72/9=18 MHz
+	 TIM3->PSC = 3; //72/4=18 MHz
 	 TIM3->DIER |= TIM_DIER_UIE;
 
 	 if(ModemConfig.modem > MODEM_9600)
@@ -905,6 +905,7 @@ void ModemInit(void)
 		demodCount = 1;
 		N = N9600;
 		baudRate = 9600.f;
+		markFreq = 38400.f / (float)DAC_SINE_SIZE; //use as DAC sample rate
 
 		demodState[0].pllStep = PLL9600_STEP;
 		demodState[0].pllLockedAdjust = PLL9600_LOCKED_TUNE;
@@ -925,8 +926,8 @@ void ModemInit(void)
 
 	TIM2->CR1 |= TIM_CR1_CEN; //enable DMA timer
 
-	markStep = 4000000 / (DAC_SINE_SIZE * markFreq) - 1;
-	spaceStep = 4000000 / (DAC_SINE_SIZE * spaceFreq) - 1;
+	markStep = 18000000 / (DAC_SINE_SIZE * markFreq) - 1;
+	spaceStep = 18000000 / (DAC_SINE_SIZE * spaceFreq) - 1;
 	baudRateStep = 18000000 / baudRate - 1;
 
 

Src/drivers/uart.c

@@ -22,6 +22,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include "common.h"
 #include <string.h>
 #include "digipeater.h"
+#include "kiss.h"
 
 Uart Uart1, Uart2, UartUsb;
 
@@ -30,28 +31,22 @@ static void handleInterrupt(Uart *port)
 	if(port->port->SR & USART_SR_RXNE) //byte received
 	{
 		port->port->SR &= ~USART_SR_RXNE;
-		port->rxBuffer[port->rxBufferHead++] = port->port->DR; //store it
+		uint8_t data = port->port->DR;
+		port->rxBuffer[port->rxBufferHead++] = data; //store it
 		port->rxBufferHead %= UART_BUFFER_SIZE;
 
+		KissParse(port, data);
 		TermHandleSpecial(port);
 
-		if(port->mode == MODE_KISS)
-			port->kissTimer = SysTickGet() + (5000 / SYSTICK_INTERVAL); //set timeout to 5s in KISS mode
 	}
 	if(port->port->SR & USART_SR_IDLE) //line is idle, end of data reception
 	{
 		port->port->DR; //reset idle flag by dummy read
 		if(port->rxBufferHead != 0)
 		{
-			if((port->rxBuffer[0] == 0xC0) && (port->rxBuffer[port->rxBufferHead - 1] == 0xC0)) //data starts with 0xc0 and ends with 0xc0 - this is a KISS frame
-			{
-				port->rxType = DATA_KISS;
-				port->kissTimer = 0;
-			}
-			else if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
+			if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
 			{
 				port->rxType = DATA_TERM;
-				port->kissTimer = 0;
 			}
 		}
 	}
@@ -59,7 +54,7 @@ static void handleInterrupt(Uart *port)
 	{
 		if((port->txBufferHead != port->txBufferTail) || port->txBufferFull) //if there is anything to transmit
 		{
-			port->port->DR = port->txBuffer[port->txBufferTail++]; //push it to the refister
+			port->port->DR = port->txBuffer[port->txBufferTail++];
 			port->txBufferTail %= UART_BUFFER_SIZE;
 			port->txBufferFull = 0;
 		}
@@ -68,13 +63,6 @@ static void handleInterrupt(Uart *port)
 			port->port->CR1 &= ~USART_CR1_TXEIE;
 		}
 	}
-
-	if((port->kissTimer > 0) && (SysTickGet() >= port->kissTimer)) //KISS timer timeout
-	{
-		port->kissTimer = 0;
-		port->rxBufferHead = 0;
-		memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
-	}
 }
 
 void USART1_IRQHandler(void) __attribute__ ((interrupt));
@@ -160,10 +148,11 @@ void UartInit(Uart *port, USART_TypeDef *uart, uint32_t baud)
 	port->txBufferFull = 0;
 	port->mode = MODE_KISS;
 	port->enabled = 0;
-	port->kissTimer = 0;
+	port->kissBufferHead = 0;
 	port->lastRxBufferHead = 0;
 	memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
 	memset(port->txBuffer, 0, sizeof(port->txBuffer));
+	memset(port->kissBuffer, 0, sizeof(port->kissBuffer));
 }
 
 
@@ -235,12 +224,3 @@ void UartClearRx(Uart *port)
 	port->rxType = DATA_NOTHING;
 }
 
-void UartHandleKissTimeout(Uart *port)
-{
-	if((port->kissTimer > 0) && (SysTickGet() >= port->kissTimer)) //KISS timer timeout
-	{
-		port->kissTimer = 0;
-		port->rxBufferHead = 0;
-		memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
-	}
-}

Src/kiss.c

@@ -0,0 +1,98 @@
+/*
+Copyright 2020-2023 Piotr Wilkon
+
+This file is part of VP-Digi.
+
+VP-Digi is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+VP-Digi is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "kiss.h"
+#include "ax25.h"
+#include "digipeater.h"
+
+void KissSend(Uart *port, uint8_t *buf, uint16_t size)
+{
+	if(port->mode == MODE_KISS)
+	{
+		UartSendByte(port, 0xC0);
+		UartSendByte(port, 0x00);
+		for(uint16_t i = 0; i < size; i++)
+		{
+			if(buf[i] == 0xC0) //frame end in data
+			{
+				UartSendByte(port, 0xDB); //frame escape
+				UartSendByte(port, 0xDC); //transposed frame end
+			}
+			else if(buf[i] == 0xDB) //frame escape in data
+			{
+				UartSendByte(port, 0xDB); //frame escape
+				UartSendByte(port, 0xDD); //transposed frame escape
+			}
+			else
+				UartSendByte(port, buf[i]);
+		}
+		UartSendByte(port, 0xC0);
+	}
+}
+
+
+void KissParse(Uart *port, uint8_t data)
+{
+	if(data == 0xC0) //frame end marker
+	{
+		if(port->kissBufferHead < 16) //command+source+destination+Control=16
+		{
+			port->kissBufferHead = 0;
+			return;
+		}
+
+		if((port->kissBuffer[0] & 0xF) != 0) //check if this is an actual frame
+		{
+			port->kissBufferHead = 0;
+			return;
+		}
+
+		//simple sanity check
+		//check if LSbits in the first 13 bytes are set to 0
+		//they should always be in an AX.25 frame
+		for(uint8_t i = 0; i < 13; i++)
+		{
+			if((port->kissBuffer[i + 1] & 1) != 0)
+			{
+				port->kissBufferHead = 0;
+				return;
+			}
+		}
+
+		Ax25WriteTxFrame(&port->kissBuffer[1], port->kissBufferHead - 1);
+		DigiStoreDeDupe(&port->kissBuffer[1], port->kissBufferHead - 1);
+		port->kissBufferHead = 0;
+		return;
+	}
+	else if(port->kissBufferHead > 0)
+	{
+		if((data == 0xDC) && (port->kissBuffer[port->kissBufferHead - 1] == 0xDB)) //escape character with transposed frame end
+		{
+			port->kissBuffer[port->kissBufferHead - 1] = 0xC0;
+			return;
+		}
+		else if((data == 0xDD) && (port->kissBuffer[port->kissBufferHead - 1] == 0xDB)) //escape character with transposed escape character
+		{
+			port->kissBuffer[port->kissBufferHead - 1] = 0xDB;
+			return;
+		}
+	}
+	port->kissBuffer[port->kissBufferHead++] = data;
+	port->kissBufferHead %= sizeof(port->kissBuffer);
+}

Src/main.c

@@ -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 = 1;
+	ModemConfig.usePWM = 1; //use PWM by default
 	ModemConfig.flatAudioIn = 0;
 	Ax25Config.quietTime = 300;
 	Ax25Config.txDelayLength = 300;
@@ -291,7 +291,6 @@ int main(void)
 		  TermParse(&Uart2);
 		  UartClearRx(&Uart2);
 	  }
-	  UartHandleKissTimeout(&UartUsb);
 
 	  BeaconCheck(); //check beacons
 

Src/terminal.c

@@ -23,6 +23,7 @@ along with VP-DigiConfig.  If not, see <http://www.gnu.org/licenses/>.
 #include "drivers/modem.h"
 #include "ax25.h"
 #include "drivers/systick.h"
+#include "kiss.h"
 
 void TermHandleSpecial(Uart *u)
 {
@@ -57,25 +58,13 @@ void TermHandleSpecial(Uart *u)
 
 }
 
-
-static void sendKiss(Uart *port, uint8_t *buf, uint16_t len)
-{
-	if(port->mode == MODE_KISS) //check if KISS mode
-	{
-		UartSendByte(port, 0xc0); //send data in kiss format
-		UartSendByte(port, 0x00);
-		UartSendString(port, buf, len);
-		UartSendByte(port, 0xc0);
-	}
-}
-
 void TermSendToAll(enum UartMode mode, uint8_t *data, uint16_t size)
 {
 	if(MODE_KISS == mode)
 	{
-		sendKiss(&Uart1, data, size);
-		sendKiss(&Uart2, data, size);
-		sendKiss(&UartUsb, data, size);
+		KissSend(&Uart1, data, size);
+		KissSend(&Uart2, data, size);
+		KissSend(&UartUsb, data, size);
 	}
 	else if(MODE_MONITOR == mode)
 	{
@@ -86,7 +75,6 @@ void TermSendToAll(enum UartMode mode, uint8_t *data, uint16_t size)
 		if(Uart2.mode == MODE_MONITOR)
 			UartSendString(&Uart2, data, size);
 	}
-
 }
 
 void TermSendNumberToAll(enum UartMode mode, int32_t n)
@@ -403,14 +391,6 @@ void TermParse(Uart *src)
 		src->mode = MODE_MONITOR;
 		return;
 	}
-	/*
-	 * KISS parsing
-	 */
-	else if((src->mode == MODE_KISS) && (src->rxType == DATA_KISS))
-	{
-		Ax25TxKiss(src->rxBuffer, src->rxBufferHead);
-		return;
-	}
 	/*
 	 * Monitor mode handling
 	 */

Src/usbd_cdc_if.c

@@ -26,6 +26,7 @@
 #include "drivers/uart.h"
 #include "drivers/systick.h"
 #include "terminal.h"
+#include "kiss.h"
 /* USER CODE END INCLUDE */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -274,6 +275,7 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
 	for(uint16_t i = 0; i < *Len; i++)
 	{
 		UartUsb.rxBuffer[UartUsb.rxBufferHead++] = Buf[i];
+		KissParse(&UartUsb, Buf[i]);
 		UartUsb.rxBufferHead %= UART_BUFFER_SIZE;
 	}
 
@@ -322,20 +324,11 @@ uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
 /* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */
 static void handleUsbInterrupt(Uart *port)
 {
-	if(port->mode == MODE_KISS)
-		port->kissTimer = SysTickGet() + (5000 / SYSTICK_INTERVAL); //set timeout to 5s in KISS mode
-
 	if(port->rxBufferHead != 0)
 	{
-		if((port->rxBuffer[0] == 0xC0) && (port->rxBuffer[port->rxBufferHead - 1] == 0xC0)) //data starts with 0xc0 and ends with 0xc0 - this is a KISS frame
-		{
-			port->rxType = DATA_KISS;
-			port->kissTimer = 0;
-		}
-		else if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
+		if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
 		{
 			port->rxType = DATA_TERM;
-			port->kissTimer = 0;
 		}
 	}
 }

vp-digi Debug.cfg

@@ -1,35 +0,0 @@
-# This is an NUCLEO-F103RB board with a single STM32F103RBTx chip
-#
-# Generated by System Workbench for STM32
-# Take care that such file, as generated, may be overridden without any early notice. Please have a look to debug launch configuration setup(s)
-
-source [find interface/stlink.cfg]
-
-set WORKAREASIZE 0x5000
-
-transport select "hla_swd"
-
-set CHIPNAME STM32F103RBTx
-set BOARDNAME NUCLEO-F103RB
-
-# CHIPNAMES state
-set CHIPNAME_CPU0_ACTIVATED 1
-
-# Enable debug when in low power modes
-set ENABLE_LOW_POWER 1
-
-# Stop Watchdog counters when halt
-set STOP_WATCHDOG 1
-
-# STlink Debug clock frequency
-set CLOCK_FREQ 4000
-
-# use software system reset
-reset_config none
-set CONNECT_UNDER_RESET 0
-
-# BCTM CPU variables
-
-
-
-source [find target/stm32f1x.cfg]

vp-digi Release.cfg

@@ -1,35 +0,0 @@
-# This is an NUCLEO-F103RB board with a single STM32F103RBTx chip
-#
-# Generated by System Workbench for STM32
-# Take care that such file, as generated, may be overridden without any early notice. Please have a look to debug launch configuration setup(s)
-
-source [find interface/stlink.cfg]
-
-set WORKAREASIZE 0x5000
-
-transport select "hla_swd"
-
-set CHIPNAME STM32F103RBTx
-set BOARDNAME NUCLEO-F103RB
-
-# CHIPNAMES state
-set CHIPNAME_CPU0_ACTIVATED 1
-
-# Enable debug when in low power modes
-set ENABLE_LOW_POWER 1
-
-# Stop Watchdog counters when halt
-set STOP_WATCHDOG 1
-
-# STlink Debug clock frequency
-set CLOCK_FREQ 4000
-
-# use software system reset
-reset_config none
-set CONNECT_UNDER_RESET 0
-
-# BCTM CPU variables
-
-
-
-source [find target/stm32f1x.cfg]