ENEL400
Aloha implementation of LoRa technology
Fork of
SX1276PingPong
by 
Semtech
Diff: main.cpp
- Revision:
- 15:f790f35839db
- Parent:
- 14:c7251480feb9
- Child:
- 16:c3c6b13c3c42
diff -r c7251480feb9 -r f790f35839db main.cpp
--- a/main.cpp Wed Feb 17 09:28:29 2016 +0000
+++ b/main.cpp Tue May 31 09:52:21 2016 +0000
@@ -2,58 +2,42 @@
#include "main.h"
#include "sx1276-hal.h"
#include "debug.h"
+#include "Aloha.h"
+#include "AlohaPacket.h"
/* Set this flag to '1' to display debug messages on the console */
-#define DEBUG_MESSAGE 0
-
-/* Set this flag to '1' to use the LoRa modulation or to '0' to use FSK modulation */
-#define USE_MODEM_LORA 1
-#define USE_MODEM_FSK !USE_MODEM_LORA
+#define DEBUG_MESSAGE 1
#define RF_FREQUENCY 868000000 // Hz
#define TX_OUTPUT_POWER 14 // 14 dBm
-
-#if USE_MODEM_LORA == 1
+#define LORA_BANDWIDTH 2 // [0: 125 kHz,
+ // 1: 250 kHz,
+ // 2: 500 kHz,
+ // 3: Reserved]
+#define LORA_SPREADING_FACTOR 7 // [SF7..SF12]
+#define LORA_CODINGRATE 1 // [1: 4/5,
+ // 2: 4/6,
+ // 3: 4/7,
+ // 4: 4/8]
+#define LORA_PREAMBLE_LENGTH 8 // Same for Tx and Rx
+#define LORA_SYMBOL_TIMEOUT 5 // Symbols
+#define LORA_FIX_LENGTH_PAYLOAD_ON false
+#define LORA_FHSS_ENABLED false
+#define LORA_NB_SYMB_HOP 4
+#define LORA_IQ_INVERSION_ON false
+#define LORA_CRC_ENABLED true
- #define LORA_BANDWIDTH 2 // [0: 125 kHz,
- // 1: 250 kHz,
- // 2: 500 kHz,
- // 3: Reserved]
- #define LORA_SPREADING_FACTOR 7 // [SF7..SF12]
- #define LORA_CODINGRATE 1 // [1: 4/5,
- // 2: 4/6,
- // 3: 4/7,
- // 4: 4/8]
- #define LORA_PREAMBLE_LENGTH 8 // Same for Tx and Rx
- #define LORA_SYMBOL_TIMEOUT 5 // Symbols
- #define LORA_FIX_LENGTH_PAYLOAD_ON false
- #define LORA_FHSS_ENABLED false
- #define LORA_NB_SYMB_HOP 4
- #define LORA_IQ_INVERSION_ON false
- #define LORA_CRC_ENABLED true
-
-#elif USE_MODEM_FSK == 1
-
- #define FSK_FDEV 25000 // Hz
- #define FSK_DATARATE 19200 // bps
- #define FSK_BANDWIDTH 50000 // Hz
- #define FSK_AFC_BANDWIDTH 83333 // Hz
- #define FSK_PREAMBLE_LENGTH 5 // Same for Tx and Rx
- #define FSK_FIX_LENGTH_PAYLOAD_ON false
- #define FSK_CRC_ENABLED true
-
-#else
- #error "Please define a modem in the compiler options."
-#endif
#define RX_TIMEOUT_VALUE 3500000 // in us
-#define BUFFER_SIZE 32 // Define the payload size here
+#define BUFFER_SIZE 4 // Define the payload size here
-#if( defined ( TARGET_KL25Z ) || defined ( TARGET_LPC11U6X ) )
DigitalOut led(LED2);
-#else
-DigitalOut led(LED1);
-#endif
+
+uint16_t BufferSize = BUFFER_SIZE;
+uint8_t Buffer[BUFFER_SIZE];
+
+int16_t RssiValue = 0.0;
+int8_t SnrValue = 0.0;
/*
* Global variables declarations
@@ -76,6 +60,7 @@
volatile AppStates_t State = LOWPOWER;
+
/*!
* Radio events function pointer
*/
@@ -86,22 +71,24 @@
*/
SX1276MB1xAS Radio( NULL );
-const uint8_t PingMsg[] = "PING";
-const uint8_t PongMsg[] = "PONG";
-
-uint16_t BufferSize = BUFFER_SIZE;
-uint8_t Buffer[BUFFER_SIZE];
+// aloha protocol
+Aloha aloha;
-int16_t RssiValue = 0.0;
-int8_t SnrValue = 0.0;
-
-int main()
+void setExpire()
{
- uint8_t i;
- bool isMaster = true;
-
- debug( "\n\n\r SX1276 Ping Pong Demo Application \n\n\r" );
+ if (aloha.attempts >= ALOHA_MAX_ATTEMPT)
+ {
+ aloha.state = Aloha::EXPIRED;
+ }
+ else
+ {
+ aloha.state = Aloha::RETRANSMIT;
+ aloha.delay = aloha.delay * aloha.delay;
+ }
+}
+void RadioInit()
+{
// Initialize Radio driver
RadioEvents.TxDone = OnTxDone;
RadioEvents.RxDone = OnRxDone;
@@ -110,23 +97,18 @@
RadioEvents.RxTimeout = OnRxTimeout;
Radio.Init( &RadioEvents );
- // verify the connection with the board
+ // detect radio hardware
while( Radio.Read( REG_VERSION ) == 0x00 )
{
- debug( "Radio could not be detected!\n\r", NULL );
+ printf( "Radio could not be detected!\n\r" );
wait( 1 );
}
-
- debug_if( ( DEBUG_MESSAGE & ( Radio.DetectBoardType( ) == SX1276MB1LAS ) ) , "\n\r > Board Type: SX1276MB1LAS < \n\r" );
- debug_if( ( DEBUG_MESSAGE & ( Radio.DetectBoardType( ) == SX1276MB1MAS ) ) , "\n\r > Board Type: SX1276MB1MAS < \n\r" );
+ printf("RadioRegVersion: %d\r\n", Radio.Read( REG_VERSION ));
+ // set radio frequency channel
Radio.SetChannel( RF_FREQUENCY );
-
-#if USE_MODEM_LORA == 1
- debug_if( LORA_FHSS_ENABLED, "\n\n\r > LORA FHSS Mode < \n\n\r");
- debug_if( !LORA_FHSS_ENABLED, "\n\n\r > LORA Mode < \n\n\r");
-
+ // set radio parameter
Radio.SetTxConfig( MODEM_LORA, TX_OUTPUT_POWER, 0, LORA_BANDWIDTH,
LORA_SPREADING_FACTOR, LORA_CODINGRATE,
LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
@@ -138,171 +120,76 @@
LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON, 0,
LORA_CRC_ENABLED, LORA_FHSS_ENABLED, LORA_NB_SYMB_HOP,
LORA_IQ_INVERSION_ON, true );
-
-#elif USE_MODEM_FSK == 1
+}
+
- debug("\n\n\r > FSK Mode < \n\n\r");
- Radio.SetTxConfig( MODEM_FSK, TX_OUTPUT_POWER, FSK_FDEV, 0,
- FSK_DATARATE, 0,
- FSK_PREAMBLE_LENGTH, FSK_FIX_LENGTH_PAYLOAD_ON,
- FSK_CRC_ENABLED, 0, 0, 0, 2000000 );
+int main()
+{
+ RadioInit();
- Radio.SetRxConfig( MODEM_FSK, FSK_BANDWIDTH, FSK_DATARATE,
- 0, FSK_AFC_BANDWIDTH, FSK_PREAMBLE_LENGTH,
- 0, FSK_FIX_LENGTH_PAYLOAD_ON, 0, FSK_CRC_ENABLED,
- 0, 0, false, true );
-
-#else
-
-#error "Please define a modem in the compiler options."
-
-#endif
-
- debug_if( DEBUG_MESSAGE, "Starting Ping-Pong loop\r\n" );
-
- led = 0;
-
- Radio.Rx( RX_TIMEOUT_VALUE );
-
- while( 1 )
+ while (1)
{
switch( State )
{
case RX:
- if( isMaster == true )
+ // if the receive frame is an ack, then cancel the timer
+ // otherwise process the frame
+ HeaderStruct header;
+ memset(&header, 0, sizeof(header));
+
+ if (header.fid == 0x01)
{
- if( BufferSize > 0 )
- {
- if( strncmp( ( const char* )Buffer, ( const char* )PongMsg, 4 ) == 0 )
- {
- led = !led;
- debug( "...Pong\r\n" );
- // Send the next PING frame
- strcpy( ( char* )Buffer, ( char* )PingMsg );
- // We fill the buffer with numbers for the payload
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- else if( strncmp( ( const char* )Buffer, ( const char* )PingMsg, 4 ) == 0 )
- { // A master already exists then become a slave
- debug( "...Ping\r\n" );
- led = !led;
- isMaster = false;
- // Send the next PONG frame
- strcpy( ( char* )Buffer, ( char* )PongMsg );
- // We fill the buffer with numbers for the payload
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- else // valid reception but neither a PING or a PONG message
- { // Set device as master ans start again
- isMaster = true;
- Radio.Rx( RX_TIMEOUT_VALUE );
- }
- }
+ aloha.AlohaAckTimeout.detach();
}
- else
- {
- if( BufferSize > 0 )
- {
- if( strncmp( ( const char* )Buffer, ( const char* )PingMsg, 4 ) == 0 )
- {
- led = !led;
- debug( "...Ping\r\n" );
- // Send the reply to the PING string
- strcpy( ( char* )Buffer, ( char* )PongMsg );
- // We fill the buffer with numbers for the payload
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- else // valid reception but not a PING as expected
- { // Set device as master and start again
- isMaster = true;
- Radio.Rx( RX_TIMEOUT_VALUE );
- }
- }
- }
- State = LOWPOWER;
+
+ // TODO: process the frame
break;
- case TX:
- led = !led;
- if( isMaster == true )
- {
- debug( "Ping...\r\n" );
- }
- else
- {
- debug( "Pong...\r\n" );
- }
- Radio.Rx( RX_TIMEOUT_VALUE );
- State = LOWPOWER;
+ case TX:
+ // transmit done
+ // then set state to aloha pending and start the timer
+ aloha.state = Aloha::PENDING;
+ aloha.delay = Radio.Random();
+ aloha.AlohaAckTimeout.detach();
+ aloha.AlohaAckTimeout.attach_us(&setExpire, aloha.delay);
+ aloha.attempts += 1;
break;
case RX_TIMEOUT:
- if( isMaster == true )
- {
- // Send the next PING frame
- strcpy( ( char* )Buffer, ( char* )PingMsg );
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- else
- {
- Radio.Rx( RX_TIMEOUT_VALUE );
- }
- State = LOWPOWER;
+ // enter listening mode
break;
case RX_ERROR:
- // We have received a Packet with a CRC error, send reply as if packet was correct
- if( isMaster == true )
- {
- // Send the next PING frame
- strcpy( ( char* )Buffer, ( char* )PingMsg );
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- else
- {
- // Send the next PONG frame
- strcpy( ( char* )Buffer, ( char* )PongMsg );
- for( i = 4; i < BufferSize; i++ )
- {
- Buffer[i] = i - 4;
- }
- wait_ms( 10 );
- Radio.Send( Buffer, BufferSize );
- }
- State = LOWPOWER;
+ // we don't handle crc failed situation
break;
case TX_TIMEOUT:
- Radio.Rx( RX_TIMEOUT_VALUE );
- State = LOWPOWER;
+ // we don't handle hardware error
break;
case LOWPOWER:
break;
default:
- State = LOWPOWER;
+ break;
+ }
+
+ switch (aloha.state)
+ {
+ case Aloha::IDLE:
+ // transmit packet if any
+ break;
+
+ case Aloha::PENDING:
+ // set rx time
break;
- }
+
+ case Aloha::RETRANSMIT:
+ // send the packet again
+ // and setup the timer with new backoff delay
+ aloha.AlohaAckTimeout.attach(&setExpire, aloha.delay);
+ aloha.state = Aloha::PENDING;
+ break;
+ case Aloha::EXPIRED:
+ // give up the transmission
+ // back to idle
+ aloha.state = Aloha::IDLE;
+ break;
+ }
}
}
@@ -310,7 +197,7 @@
{
Radio.Sleep( );
State = TX;
- debug_if( DEBUG_MESSAGE, "> OnTxDone\n\r" );
+ printf( "> OnTxDone\n\r" );
}
void OnRxDone( uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr)
@@ -321,14 +208,14 @@
RssiValue = rssi;
SnrValue = snr;
State = RX;
- debug_if( DEBUG_MESSAGE, "> OnRxDone\n\r" );
+ printf( "> OnRxDone\n\r" );
}
void OnTxTimeout( void )
{
Radio.Sleep( );
State = TX_TIMEOUT;
- debug_if( DEBUG_MESSAGE, "> OnTxTimeout\n\r" );
+ printf( "> OnTxTimeout\n\r" );
}
void OnRxTimeout( void )
@@ -336,13 +223,12 @@
Radio.Sleep( );
Buffer[ BufferSize ] = 0;
State = RX_TIMEOUT;
- debug_if( DEBUG_MESSAGE, "> OnRxTimeout\n\r" );
+ printf( "> OnRxTimeout\n\r" );
}
void OnRxError( void )
{
Radio.Sleep( );
State = RX_ERROR;
- debug_if( DEBUG_MESSAGE, "> OnRxError\n\r" );
+ printf( "> OnRxError\n\r" );
}
-