diff options
Diffstat (limited to 'libloragw/src/loragw_hal.c')
| -rw-r--r-- | libloragw/src/loragw_hal.c | 74 |
1 files changed, 42 insertions, 32 deletions
diff --git a/libloragw/src/loragw_hal.c b/libloragw/src/loragw_hal.c index 4319d5e..3ab1cb5 100644 --- a/libloragw/src/loragw_hal.c +++ b/libloragw/src/loragw_hal.c @@ -20,7 +20,6 @@ Maintainer: Sylvain Miermont #include <stdint.h> /* C99 types */ #include <stdbool.h> /* bool type */ #include <stdio.h> /* printf fprintf */ -#include <math.h> /* NaN */ #include <string.h> /* memcpy */ #include "loragw_reg.h" @@ -45,6 +44,7 @@ Maintainer: Sylvain Miermont #define IF_HZ_TO_REG(f) (f << 5)/15625 #define SET_PPM_ON(bw,dr) (((bw == BW_125KHZ) && ((dr == DR_LORA_SF11) || (dr == DR_LORA_SF12))) || ((bw == BW_250KHZ) && (dr == DR_LORA_SF12))) +#define TRACE() fprintf(stderr, "@ %s %d\n", __FUNCTION__, __LINE__); /* -------------------------------------------------------------------------- */ /* --- PRIVATE CONSTANTS ---------------------------------------------------- */ @@ -763,13 +763,13 @@ int lgw_receive(uint8_t max_pkt, struct lgw_pkt_rx_s *pkt_data) { int nb_pkt_fetch; /* loop variable and return value */ struct lgw_pkt_rx_s *p; /* pointer to the current structure in the struct array */ uint8_t buff[255+RX_METADATA_NB]; /* buffer to store the result of SPI read bursts */ - int sz; /* size of the payload, uses to address metadata */ + unsigned sz; /* size of the payload, uses to address metadata */ int ifmod; /* type of if_chain/modem a packet was received by */ int stat_fifo; /* the packet status as indicated in the FIFO */ uint32_t raw_timestamp; /* timestamp when internal 'RX finished' was triggered */ + uint32_t delay_x, delay_y, delay_z; /* temporary variable for timestamp offset calculation */ uint32_t timestamp_correction; /* correction to account for processing delay */ - uint8_t sf, cr, bw; /* used to calculate timestamp correction */ - uint8_t crc_en, ppm; /* used to calculate timestamp correction */ + uint32_t sf, cr, bw_pow, crc_en, ppm; /* used to calculate timestamp correction */ /* check if the gateway is running */ if (lgw_is_started == false) { @@ -864,41 +864,51 @@ int lgw_receive(uint8_t max_pkt, struct lgw_pkt_rx_s *pkt_data) { default: p->coderate = CR_UNDEFINED; } - /* timestamp correction code */ + /* determine if 'PPM mode' is on, needed for timestamp correction */ + if (SET_PPM_ON(p->bandwidth,p->datarate)) { + ppm = 1; + } else { + ppm = 0; + } + + /* timestamp correction code, base delay */ if (ifmod == IF_LORA_STD) { /* if packet was received on the stand-alone lora modem */ switch (lora_rx_bw) { case BW_125KHZ: - timestamp_correction = 64; - bw = 1; + delay_x = 64; + bw_pow = 1; break; case BW_250KHZ: - timestamp_correction = 32; - bw = 2; + delay_x = 32; + bw_pow = 2; break; case BW_500KHZ: - timestamp_correction = 16; - bw = 4; + delay_x = 16; + bw_pow = 4; break; default: DEBUG_PRINTF("ERROR: UNEXPECTED VALUE %d IN SWITCH STATEMENT\n", p->bandwidth); - timestamp_correction = 0; - bw = 0; + delay_x = 0; + bw_pow = 0; } } else { /* packet was received on one of the sensor channels = 125kHz */ - timestamp_correction = 114; - bw = 1; + delay_x = 114; + bw_pow = 1; } - if (SET_PPM_ON(p->bandwidth,p->datarate)) { - ppm = 1; - } else { - ppm = 0; - } - if ((2*(sz + 2*crc_en) - sf +7) <= 0) { /* payload fits entirely in first 8 symbols */ - timestamp_correction += (((1<<(sf-1)) * (sf+1)) + (3*(1<<(sf-4))))/bw; - timestamp_correction += 32 * (2*(sz+2*crc_en) + 5)/bw; + + /* timestamp correction code, variable delay */ + if ((sf >= 6) && (sf <= 12) && (bw_pow > 0)) { + if ((2*(sz + 2*crc_en) - (sf-7)) <= 0) { /* payload fits entirely in first 8 symbols */ + delay_y = ( ((1<<(sf-1)) * (sf+1)) + (3 * (1<<(sf-4))) ) / bw_pow; + delay_z = 32 * (2*(sz+2*crc_en) + 5) / bw_pow; + } else { + delay_y = ( ((1<<(sf-1)) * (sf+1)) + ((4 - ppm) * (1<<(sf-4))) ) / bw_pow; + delay_z = (16 + 4*cr) * (((2*(sz+2*crc_en)-sf+6) % (sf - 2*ppm)) + 1) / bw_pow; + } + timestamp_correction = delay_x + delay_y + delay_z; } else { - timestamp_correction += (((1<<(sf-1)) * (sf+1)) + ((4.0-ppm)/4.0*(1<<(sf-2))))/bw; - timestamp_correction += (16 + 4*cr) * (((2*(sz+2*crc_en)-sf + 6) % (sf-2*ppm) +1) / bw); + timestamp_correction = 0; + DEBUG_MSG("WARNING: invalid packet, no timestamp correction\n"); } } else if (ifmod == IF_FSK_STD) { DEBUG_MSG("Note: FSK packet\n"); @@ -910,9 +920,9 @@ int lgw_receive(uint8_t max_pkt, struct lgw_pkt_rx_s *pkt_data) { } p->modulation = MOD_FSK; p->rssi = (RSSI_OFFSET_FSK + (float)buff[sz+5])/RSSI_SLOPE_FSK; - p->snr = NAN; - p->snr_min = NAN; - p->snr_max = NAN; + p->snr = -128.0; + p->snr_min = -128.0; + p->snr_max = -128.0; p->bandwidth = fsk_rx_bw; p->datarate = fsk_rx_dr; p->coderate = CR_UNDEFINED; @@ -921,10 +931,10 @@ int lgw_receive(uint8_t max_pkt, struct lgw_pkt_rx_s *pkt_data) { DEBUG_MSG("ERROR: UNEXPECTED PACKET ORIGIN\n"); p->status = STAT_UNDEFINED; p->modulation = MOD_UNDEFINED; - p->rssi = NAN; - p->snr = NAN; - p->snr_min = NAN; - p->snr_max = NAN; + p->rssi = -128.0; + p->snr = -128.0; + p->snr_min = -128.0; + p->snr_max = -128.0; p->bandwidth = BW_UNDEFINED; p->datarate = DR_UNDEFINED; p->coderate = CR_UNDEFINED; |