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[SX127x] Added public method to convert from bytes to symbols

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This commit is contained in:
jgromes 2023-11-12 13:28:06 +01:00
parent 140d35af81
commit c170bc096f
2 changed files with 39 additions and 16 deletions
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47
src/modules/SX127x/SX127x.cpp
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@ -1231,28 +1231,45 @@ int16_t SX127x::variablePacketLengthMode(uint8_t maxLen) {
return(SX127x::setPacketMode(RADIOLIB_SX127X_PACKET_VARIABLE, maxLen)); return(SX127x::setPacketMode(RADIOLIB_SX127X_PACKET_VARIABLE, maxLen));
} }
float SX127x::getNumSymbols(size_t len) {
// get symbol length in us
float symbolLength = (float) (uint32_t(1) << this->spreadingFactor) / (float) this->bandwidth;
// get Low Data Rate optimization flag
float de = 0;
if (symbolLength >= 16.0) {
de = 1;
}
// get explicit/implicit header enabled flag
float ih = (float) this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_1, 0, 0);
// get CRC enabled flag
float crc = (float) (this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_2, 2, 2) >> 2);
// get number of preamble symbols
float n_pre = (float) ((this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB) << 8) | this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB));
// get number of payload symbols
float n_pay = 8.0 + RADIOLIB_MAX(ceil((8.0 * (float) len - 4.0 * (float) this->spreadingFactor + 28.0 + 16.0 * crc - 20.0 * ih) / (4.0 * (float) this->spreadingFactor - 8.0 * de)) * (float) this->codingRate, 0.0);
// add 4.25 symbols for the sync
return(n_pre + n_pay + 4.25f);
}
uint32_t SX127x::getTimeOnAir(size_t len) { uint32_t SX127x::getTimeOnAir(size_t len) {
// check active modem // check active modem
uint8_t modem = getActiveModem(); uint8_t modem = getActiveModem();
if (modem == RADIOLIB_SX127X_LORA) { if (modem == RADIOLIB_SX127X_LORA) {
// Get symbol length in us // get symbol length in us
float symbolLength = (float) (uint32_t(1) << this->spreadingFactor) / (float) this->bandwidth; float symbolLength = (float) (uint32_t(1) << this->spreadingFactor) / (float) this->bandwidth;
// Get Low Data Rate optimization flag
float de = 0; // get number of symbols
if (symbolLength >= 16.0) { float n_sym = getNumSymbols(len);
de = 1;
}
// Get explicit/implicit header enabled flag
float ih = (float) this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_1, 0, 0);
// Get CRC enabled flag
float crc = (float) (this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_2, 2, 2) >> 2);
// Get number of bits preamble
float n_pre = (float) ((this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB) << 8) | this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB));
// Get number of bits payload
float n_pay = 8.0 + RADIOLIB_MAX(ceil((8.0 * (float) len - 4.0 * (float) this->spreadingFactor + 28.0 + 16.0 * crc - 20.0 * ih) / (4.0 * (float) this->spreadingFactor - 8.0 * de)) * (float) this->codingRate, 0.0);
// Get time-on-air in us // Get time-on-air in us
return ceil(symbolLength * (n_pre + n_pay + 4.25)) * 1000; return ceil(symbolLength * n_sym) * 1000;
} else if(modem == RADIOLIB_SX127X_FSK_OOK) { } else if(modem == RADIOLIB_SX127X_FSK_OOK) {
// Get number of bits preamble // Get number of bits preamble
float n_pre = (float) ((this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB_FSK) << 8) | this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB_FSK)) * 8; float n_pre = (float) ((this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB_FSK) << 8) | this->mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB_FSK)) * 8;

8
src/modules/SX127x/SX127x.h
View file

@ -818,7 +818,6 @@ class SX127x: public PhysicalLayer {
\brief Interrupt-driven receive method. DIO0 will be activated when full valid packet is received. \brief Interrupt-driven receive method. DIO0 will be activated when full valid packet is received.
\param len Expected length of packet to be received, or 0 when unused. \param len Expected length of packet to be received, or 0 when unused.
Defaults to 0, non-zero required for LoRa spreading factor 6. Defaults to 0, non-zero required for LoRa spreading factor 6.
If non-zero for LoRa spreading factor > 6, RxSingle is used and value must be given in symbols.
\param mode Receive mode to be used. Defaults to RxContinuous. \param mode Receive mode to be used. Defaults to RxContinuous.
\returns \ref status_codes \returns \ref status_codes
*/ */
@ -1046,6 +1045,13 @@ class SX127x: public PhysicalLayer {
*/ */
int16_t variablePacketLengthMode(uint8_t maxLen = RADIOLIB_SX127X_MAX_PACKET_LENGTH_FSK); int16_t variablePacketLengthMode(uint8_t maxLen = RADIOLIB_SX127X_MAX_PACKET_LENGTH_FSK);
/*!
\brief Convert from bytes to LoRa symbols.
\param len Payload length in bytes.
\returns The total number of LoRa symbols, including preamble, sync and possible header.
*/
float getNumSymbols(size_t len);
/*! /*!
\brief Get expected time-on-air for a given size of payload. \brief Get expected time-on-air for a given size of payload.
\param len Payload length in bytes. \param len Payload length in bytes.