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RadioLib - getTimeOnAir for SX127x modules

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This commit is contained in:
Jaimi5 2022-06-24 17:38:31 +02:00
parent e5e8947e94
commit 298dbe8e5c
2 changed files with 23 additions and 10 deletions
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24
src/modules/SX127x/SX127x.cpp
View file

@ -148,16 +148,7 @@ int16_t SX127x::transmit(uint8_t* data, size_t len, uint8_t addr) {
uint32_t start = 0;
if(modem == RADIOLIB_SX127X_LORA) {
// calculate timeout (150 % of expected time-one-air)
float symbolLength = (float)(uint32_t(1) <<_sf) / (float)_bw;
float de = 0;
if(symbolLength >= 16.0) {
de = 1;
}
float ih = (float)_mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_1, 0, 0);
float crc = (float)(_mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_2, 2, 2) >> 2);
float n_pre = (float)((_mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB) << 8) | _mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB));
float n_pay = 8.0 + max(ceil((8.0 * (float)len - 4.0 * (float)_sf + 28.0 + 16.0 * crc - 20.0 * ih)/(4.0 * (float)_sf - 8.0 * de)) * (float)_cr, 0.0);
uint32_t timeout = ceil(symbolLength * (n_pre + n_pay + 4.25) * 1500.0);
uint32_t timeout = getTimeOnAir(len) * 1500.0;
// start transmission
state = startTransmit(data, len, addr);
@ -1047,6 +1038,19 @@ int16_t SX127x::variablePacketLengthMode(uint8_t maxLen) {
return(SX127x::setPacketMode(RADIOLIB_SX127X_PACKET_VARIABLE, maxLen));
}
uint32_t SX127x::getTimeOnAir(size_t len) {
float symbolLength = (float) (uint32_t(1) << _sf) / (float) _bw;
float de = 0;
if (symbolLength >= 16.0) {
de = 1;
}
float ih = (float) _mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_1, 0, 0);
float crc = (float) (_mod->SPIgetRegValue(RADIOLIB_SX127X_REG_MODEM_CONFIG_2, 2, 2) >> 2);
float n_pre = (float) ((_mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_MSB) << 8) | _mod->SPIgetRegValue(RADIOLIB_SX127X_REG_PREAMBLE_LSB));
float n_pay = 8.0 + max(ceil((8.0 * (float) len - 4.0 * (float) _sf + 28.0 + 16.0 * crc - 20.0 * ih) / (4.0 * (float) _sf - 8.0 * de)) * (float) _cr, 0.0);
return ceil(symbolLength * (n_pre + n_pay + 4.25));
}
int16_t SX127x::setCrcFiltering(bool crcOn) {
_crcOn = crcOn;

9
src/modules/SX127x/SX127x.h
View file

@ -980,6 +980,15 @@ class SX127x: public PhysicalLayer {
*/
int16_t variablePacketLengthMode(uint8_t maxLen = RADIOLIB_SX127X_MAX_PACKET_LENGTH_FSK);
/*!
\brief Get expected time-on-air for a given size of payload
\param len Payload length in bytes.
\returns Expected time-on-air in microseconds.
*/
uint32_t getTimeOnAir(size_t len);
/*!
\brief Enable CRC filtering and generation.