Using Spreading factor 12 on NUCLEO-WL55JC1 LoRa boards

[JMala.3]

I have 2 NUCLEO-WL55JC1 boards I am using to communicate using LoRa.  The Tx board sends a message every 10 seconds, the Rx board receives the message and lights up an LED..I have this working at SF7, the same spreading factor as the ping-pong example I copied the code from, but if I try to change this to SF12 (on both Tx and Rx projects) the Rx board never receives messages.

Any ideas on how I can fix this?  Her is the code

#include <stdio.h>
#include <radio_driver.h>
#include "types.h"
#include "radio.h"

#define RF_FREQUENCY                                924000000     /* Hz */
#define TX_OUTPUT_POWER                             14            /* dBm */
#define LORA_BANDWIDTH                              LORA_BW_500   /* KHz */
#define LORA_SPREADING_FACTOR                       LORA_SF9
#define LORA_CODINGRATE                             LORA_CR_4_5
#define LORA_PREAMBLE_LENGTH                        8             /* Same for Tx and Rx */
#define LORA_SYMBOL_TIMEOUT                         5             /* Symbols */
 
#define LORA_RX_TIMEOUT                             10000         /* milliseconds */
#define RADIO_RX_BUFFER_SIZE                        10
#define ZERO_OFFSET                                 0

typedef enum {
    RADIO_STATE_IDLE,
    RADIO_STATE_RX_COMPLETE,
    RADIO_STATE_RX_ERROR
} RADIO_STATES;

PacketParams_t                  Radio_PacketParams;
const RadioLoRaBandwidths_t     Radio_Bandwidths[] = { LORA_BW_125, LORA_BW_250, LORA_BW_500 };
RADIO_STATES Radio_State;

const char Radio_TimeoutText[] = "Rx Timeout\r\n";
const char Radio_ReceivedText[] = "Rx Received\r\n";
const char Radio_InitializedText[] = "Radio Initialized\r\n";
const char Radio_CrlfText[] = "\r\n";
extern UART_HandleTypeDef huart2;

void Radio_ReceiveMsg( void );
void Radio_IrqHandler(RadioIrqMasks_t radioIrq);

/*****************************************************************************************
 * FUNCTION:	Radio_Init
 * 
 * DESCRIPTION:	Initializes LoRa Radio
 *
 * PARAMETERS:  None
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_Init(void)
{
    ModulationParams_t modulationParams;
    
    // Initialize the hardware (SPI bus, TCXO control, RF switch)
    SUBGRF_Init(Radio_IrqHandler);

    // Use DCDC converter if `DCDC_ENABLE` is defined in radio_conf.h
    // "By default, the SMPS clock detection is disabled and must be enabled before enabling the SMPS." (6.1 in RM0453)
    SUBGRF_WriteRegister(SUBGHZ_SMPSC0R, (SUBGRF_ReadRegister(SUBGHZ_SMPSC0R) | SMPS_CLK_DET_ENABLE));
    SUBGRF_SetRegulatorMode();

    // Use the whole 256-byte buffer for both TX and RX
    SUBGRF_SetBufferBaseAddress(0x00, 0x00);

    SUBGRF_SetRfFrequency(RF_FREQUENCY);
    SUBGRF_SetRfTxPower(TX_OUTPUT_POWER);
    SUBGRF_SetStopRxTimerOnPreambleDetect(FALSE);

    SUBGRF_SetPacketType(PACKET_TYPE_LORA);

    SUBGRF_WriteRegister( REG_LR_SYNCWORD, ( LORA_MAC_PRIVATE_SYNCWORD >> 8 ) & 0xFF );
    SUBGRF_WriteRegister( REG_LR_SYNCWORD + 1, LORA_MAC_PRIVATE_SYNCWORD & 0xFF );

    modulationParams.PacketType = PACKET_TYPE_LORA;
    modulationParams.Params.LoRa.Bandwidth = LORA_BANDWIDTH;
    modulationParams.Params.LoRa.CodingRate = LORA_CODINGRATE;
    modulationParams.Params.LoRa.LowDatarateOptimize = 0x00;
    modulationParams.Params.LoRa.SpreadingFactor = LORA_SPREADING_FACTOR;
    SUBGRF_SetModulationParams(&modulationParams);

    Radio_PacketParams.PacketType = PACKET_TYPE_LORA;
    Radio_PacketParams.Params.LoRa.CrcMode = LORA_CRC_ON;
    Radio_PacketParams.Params.LoRa.HeaderType = LORA_PACKET_VARIABLE_LENGTH;
    Radio_PacketParams.Params.LoRa.InvertIQ = LORA_IQ_NORMAL;
    Radio_PacketParams.Params.LoRa.PayloadLength = 0xFF;
    Radio_PacketParams.Params.LoRa.PreambleLength = LORA_PREAMBLE_LENGTH;
    SUBGRF_SetPacketParams(&Radio_PacketParams);

    //SUBGRF_SetLoRaSymbNumTimeout(LORA_SYMBOL_TIMEOUT);

    // WORKAROUND - Optimizing the Inverted IQ Operation, see DS_SX1261-2_V1.2 datasheet chapter 15.4
    // RegIqPolaritySetup @address 0x0736
    SUBGRF_WriteRegister( 0x0736, SUBGRF_ReadRegister( 0x0736 ) | ( 1 << 2 ) );
    
	HAL_UART_Transmit(&huart2, (uint8_t *)Radio_InitializedText, sizeof(Radio_InitializedText) - 1, HAL_MAX_DELAY);
    BSP_LED_On(LED_GREEN);
    Radio_State = RADIO_STATE_IDLE;
    Radio_ReceiveMsg();
}

/*****************************************************************************************
 * FUNCTION:	Radio_IrqHandler
 * 
 * DESCRIPTION:	Process a radio interrupt
 *
 * PARAMETERS:  radioIrq - Event causing the interrupt
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_IrqHandler(RadioIrqMasks_t radioIrq)
{
    switch (radioIrq)
    {
        case IRQ_TX_DONE:
            break;
        case IRQ_RX_DONE:
            Radio_State = RADIO_STATE_RX_COMPLETE;        
            break;
        case IRQ_RX_TX_TIMEOUT:
            Radio_State = RADIO_STATE_RX_ERROR;        
            break;
        case IRQ_CRC_ERROR:
            Radio_State = RADIO_STATE_RX_ERROR;        
            break;
        default:
            Radio_State = RADIO_STATE_IDLE;        
            break;
    }
}

/*****************************************************************************************
 * FUNCTION:	Radio_HandleTick
 * 
 * DESCRIPTION:	Process a Lora radio interrupt
 *
 * PARAMETERS:  radioIrq - Event causing the interrupt
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_HandleTick(void)
{
    char RxBuffer[RADIO_RX_BUFFER_SIZE];

    if(Radio_State != RADIO_STATE_IDLE)
    {
        if(Radio_State == RADIO_STATE_RX_COMPLETE)
        {
            memset(RxBuffer, 0 , sizeof(RxBuffer));
            SUBGRF_ReadBuffer( ZERO_OFFSET, (uint8_t *)RxBuffer, RADIO_RX_BUFFER_SIZE );
            strcat(RxBuffer, Radio_CrlfText);
            HAL_UART_Transmit(&huart2, (uint8_t *)RxBuffer, RADIO_RX_BUFFER_SIZE, HAL_MAX_DELAY);
            BSP_LED_On(LED_RED);
            HAL_Delay(500);
            BSP_LED_Off(LED_RED);
        }
        else if(Radio_State == RADIO_STATE_RX_ERROR)
        {
            HAL_UART_Transmit(&huart2, (uint8_t *)Radio_TimeoutText, sizeof(Radio_TimeoutText) - 1, HAL_MAX_DELAY);
        }
        Radio_ReceiveMsg();
    	Radio_State = RADIO_STATE_IDLE;
    }
}

/*****************************************************************************************
 * FUNCTION:	Radio_ReceiveMsg
 * 
 * DESCRIPTION:	Receive a message from the Roam Remote
 *
 * PARAMETERS:  None
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_ReceiveMsg( void )
{
    SUBGRF_SetDioIrqParams( IRQ_RX_DONE | IRQ_RX_TX_TIMEOUT | IRQ_CRC_ERROR | IRQ_HEADER_ERROR,
                            IRQ_RX_DONE | IRQ_RX_TX_TIMEOUT | IRQ_CRC_ERROR | IRQ_HEADER_ERROR,
                            IRQ_RADIO_NONE,
                            IRQ_RADIO_NONE );
                          
    SUBGRF_SetSwitch(RFO_LP, RFSWITCH_RX);
  
    Radio_PacketParams.Params.LoRa.PayloadLength = 0xFF;
    SUBGRF_SetPacketParams(&Radio_PacketParams);
  
    SUBGRF_SetRx(LORA_RX_TIMEOUT << 6);
}

[Tesla DeLorean]

You don't show the Tx side, but going to need 

void SUBGRF_SetTx( uint32_t timeout );

Probably going to want continuous reception so the Rx side doesn't die mid transaction.

[JMala.3]

Thanks for the reply TeslaDelorean Here is the Tx code.  Does this look OK?

I am not using SUBGRF_SetTx.  Can you recommend a value for the timeout?

#include <stdio.h>
#include <radio_driver.h>
#include "types.h"
#include "radio.h"

#define RF_FREQUENCY                                924000000     /* Hz */
#define TX_OUTPUT_POWER                             14            /* dBm */
#define LORA_BANDWIDTH                              LORA_BW_500   /* KHz */
#define LORA_SPREADING_FACTOR                       LORA_SF9
#define LORA_CODINGRATE                             LORA_CR_4_5
#define LORA_PREAMBLE_LENGTH                        8             /* Same for Tx and Rx */
#define LORA_SYMBOL_TIMEOUT                         5             /* Symbols */
 
#define LORA_RX_TIMEOUT                             10000     /* milliseconds */
#define RADIO_RX_BUFFER_SIZE                        10
#define ZERO_OFFSET                                 0

typedef enum {
    RADIO_STATE_IDLE,
    RADIO_STATE_TX_COMPLETE,
    RADIO_STATE_TX_ERROR
} RADIO_STATES;

PacketParams_t                  Radio_PacketParams;
const RadioLoRaBandwidths_t     Radio_Bandwidths[] = { LORA_BW_125, LORA_BW_250, LORA_BW_500 };
RADIO_STATES Radio_State;
const char Radio_ErrorText[] = "Tx Error\r\n";
const char Radio_TxCompleteText[] = "Tx Complete\r\n";
const char Radio_InitializedText[] = "Radio Initialized\r\n";
const char Radio_PingMsg[] = "Ping";
extern UART_HandleTypeDef huart2;

void Radio_SendMsg( UINT8 *Msg, UINT8 MsgLen );
void Radio_IrqHandler(RadioIrqMasks_t radioIrq);

/*****************************************************************************************
 * FUNCTION:	Radio_Init
 * 
 * DESCRIPTION:	Open UDP socket to simulate messages to the ICC2 simulator
 *
 * PARAMETERS:  None
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_Init(void)
{
    ModulationParams_t modulationParams;
    
    // Initialize the hardware (SPI bus, TCXO control, RF switch)
    SUBGRF_Init(Radio_IrqHandler);

    // Use DCDC converter if `DCDC_ENABLE` is defined in radio_conf.h
    // "By default, the SMPS clock detection is disabled and must be enabled before enabling the SMPS." (6.1 in RM0453)
    SUBGRF_WriteRegister(SUBGHZ_SMPSC0R, (SUBGRF_ReadRegister(SUBGHZ_SMPSC0R) | SMPS_CLK_DET_ENABLE));
    SUBGRF_SetRegulatorMode();

    // Use the whole 256-byte buffer for both TX and RX
    SUBGRF_SetBufferBaseAddress(0x00, 0x00);

    SUBGRF_SetRfFrequency(RF_FREQUENCY);
    SUBGRF_SetRfTxPower(TX_OUTPUT_POWER);
    SUBGRF_SetStopRxTimerOnPreambleDetect(FALSE);

    SUBGRF_SetPacketType(PACKET_TYPE_LORA);

    SUBGRF_WriteRegister( REG_LR_SYNCWORD, ( LORA_MAC_PRIVATE_SYNCWORD >> 8 ) & 0xFF );
    SUBGRF_WriteRegister( REG_LR_SYNCWORD + 1, LORA_MAC_PRIVATE_SYNCWORD & 0xFF );

    modulationParams.PacketType = PACKET_TYPE_LORA;
    modulationParams.Params.LoRa.Bandwidth = LORA_BANDWIDTH;
    modulationParams.Params.LoRa.CodingRate = LORA_CODINGRATE;
    modulationParams.Params.LoRa.LowDatarateOptimize = 0x00;
    modulationParams.Params.LoRa.SpreadingFactor = LORA_SPREADING_FACTOR;
    SUBGRF_SetModulationParams(&modulationParams);

    Radio_PacketParams.PacketType = PACKET_TYPE_LORA;
    Radio_PacketParams.Params.LoRa.CrcMode = LORA_CRC_ON;
    Radio_PacketParams.Params.LoRa.HeaderType = LORA_PACKET_VARIABLE_LENGTH;
    Radio_PacketParams.Params.LoRa.InvertIQ = LORA_IQ_NORMAL;
    Radio_PacketParams.Params.LoRa.PayloadLength = 0xFF;
    Radio_PacketParams.Params.LoRa.PreambleLength = LORA_PREAMBLE_LENGTH;
    SUBGRF_SetPacketParams(&Radio_PacketParams);

    //SUBGRF_SetLoRaSymbNumTimeout(LORA_SYMBOL_TIMEOUT);

    // WORKAROUND - Optimizing the Inverted IQ Operation, see DS_SX1261-2_V1.2 datasheet chapter 15.4
    // RegIqPolaritySetup @address 0x0736
    SUBGRF_WriteRegister( 0x0736, SUBGRF_ReadRegister( 0x0736 ) | ( 1 << 2 ) );

	HAL_UART_Transmit(&huart2, (uint8_t *)Radio_InitializedText, sizeof(Radio_InitializedText) - 1, HAL_MAX_DELAY);
    BSP_LED_On(LED_GREEN);
    Radio_State = RADIO_STATE_IDLE;
    Radio_SendMsg( (UINT8 *)Radio_PingMsg, sizeof(Radio_PingMsg) - 1 );
}

/*****************************************************************************************
 * FUNCTION:	Radio_IrqHandler
 * 
 * DESCRIPTION:	Process a radio interrupt
 *
 * PARAMETERS:  radioIrq - Event causing the interrupt
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_IrqHandler(RadioIrqMasks_t radioIrq)
{
    switch (radioIrq)
    {
        case IRQ_TX_DONE:
            Radio_State = RADIO_STATE_TX_COMPLETE;
            break;
        case IRQ_RX_DONE:
            break;
        case IRQ_RX_TX_TIMEOUT:
            Radio_State = RADIO_STATE_TX_ERROR;
            break;
        case IRQ_CRC_ERROR:
            break;
        default:
            Radio_State = RADIO_STATE_IDLE;        
            break;
    }
}

/*****************************************************************************************
 * FUNCTION:	Radio_HandleTick
 * 
 * DESCRIPTION:	Process a Lora radio interrupt
 *
 * PARAMETERS:  radioIrq - Event causing the interrupt
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_HandleTick(void)
{
    if(Radio_State != RADIO_STATE_IDLE)
    {
        if(Radio_State == RADIO_STATE_TX_COMPLETE)
        {
            HAL_UART_Transmit(&huart2, (uint8_t *)Radio_TxCompleteText, sizeof(Radio_TxCompleteText) - 1, HAL_MAX_DELAY);
            HAL_Delay(10000);
            BSP_LED_On(LED_RED);
            HAL_Delay(500);
            Radio_SendMsg( (UINT8 *)Radio_PingMsg, sizeof(Radio_PingMsg) - 1 );
            BSP_LED_Off(LED_RED);
        }
        else if(Radio_State == RADIO_STATE_TX_ERROR)
        {
            HAL_UART_Transmit(&huart2, (uint8_t *)Radio_ErrorText, sizeof(Radio_ErrorText) - 1, HAL_MAX_DELAY);
        }
    	Radio_State = RADIO_STATE_IDLE;
    }
}

/*****************************************************************************************
 * FUNCTION:	Radio_ReceiveMsg
 * 
 * DESCRIPTION:	Receive a message from the Roam Remote
 *
 * PARAMETERS:  None
 *
 * RETURN: 		None
 *****************************************************************************************/
void Radio_SendMsg( UINT8 *Msg, UINT8 MsgLen )
{
    SUBGRF_SetDioIrqParams( IRQ_TX_DONE | IRQ_RX_TX_TIMEOUT,
                            IRQ_TX_DONE | IRQ_RX_TX_TIMEOUT,
                            IRQ_RADIO_NONE,
                            IRQ_RADIO_NONE );
    SUBGRF_SetSwitch(RFO_LP, RFSWITCH_TX);
    // Workaround 5.1 in DS.SX1261-2.W.APP (before each packet transmission)
    SUBGRF_WriteRegister(0x0889, (SUBGRF_ReadRegister(0x0889) | 0x04));
    Radio_PacketParams.Params.LoRa.PayloadLength = MsgLen;
    SUBGRF_SetPacketParams(&Radio_PacketParams);

    SUBGRF_SendPayload((uint8_t *)Msg, MsgLen, 0);
}

[Tesla DeLorean]

SUBGRF_SetTx(11000); // 10s + 10% margin

I haven't built with this version but the older library with a slow SF12 beacon, would timeout with ST / SEMTECH examples.

Are you getting a TX_TIMEOUT error? 

Do you idle the SUBGRF_SetSwitch() at some point?

[Joe WILLIAMS]

Hello JMala.3

Your post has been reassigned to the online support team for more assistance.

Kind Regards

Joe WILLIAMS

STMicro Support

[Tesla DeLorean]

Please come back when you have an answer, dark-webbing this stuff in internal systems has significantly less reach.

[JMala.3 · Accepted solution]

I found the issue.in the function Radio_SendMsg the lines

// Workaround 5.1 in DS.SX1261-2.W.APP (before each packet transmission)
    SUBGRF_WriteRegister(0x0889, (SUBGRF_ReadRegister(0x0889) | 0x04));

Are only applicable for bandwidths less then 500kHz, for 500kHz bandwidth, the bit should be left as a zero.  I removed these line from my code and now it works.