wayne roberts
Driver library for SX1272/SX1276 transceivers
Dependents: LORA_RX LORA_TX WindConcentrator hid_test ... more
Driver library for SX1272 and SX1276 radio transceivers.
This device uses CSS modulation to provide much improved link budget. The RF hardware is same as in FSK devices, just with added LoRa spread-spectrum modem.
This library provides functions to configure radio chip and transmit & receive packets.
Using This Library
Library function service_radio() must be called continuously from main loop, to service interrupts from radio.
Board Specific implementation
FunctionPointer for rf_switch callback allows the program to implement control of RF switch unique to their board.
Example options are:
- SKY13373 for external power amplifier implementation. Requires two DigitalOut pins.
- SKY13350 using PA_BOOST. requires two DigitalOut pins.
- PE4259-63: controlled directly by radio chip, no software function needed. However, in the case of SX1276MB1xAS, the RXTX pin on IO2 should be driven by this callback function when R16 is installed (without R15) on this shield board.
Some configurations may need to force the use of RFO or PA_BOOST, or a board could offer both options. The rf_switch function pointer callback should support the implementation choice on the board.
further reading
- LoRa modulation basics (dropbox PDF)
- OpenLoRa forum
Diff: sx127x_lora.h
- Revision:
- 17:59279bc8cdab
- Parent:
- 16:3de8e1c465eb
- Child:
- 18:0ecb6adb7c0b
--- a/sx127x_lora.h Thu May 21 18:24:04 2015 +0000
+++ b/sx127x_lora.h Wed May 27 22:42:30 2015 +0000
@@ -44,6 +44,7 @@
#define REG_LR_CAD_MIN_PEAK 0x35
#define REG_LR_DETECTION_THRESHOLD 0x37
#define REG_LR_SYNC_BYTE 0x39 // default 0x12 (value of 0x21 will isolate network)
+#define REG_LR_DRIFT_INVERT 0x3b
typedef union {
struct { // sx127x register 0x12
@@ -137,18 +138,33 @@
typedef union {
struct { // sx127x register 0x33
- uint8_t chirp_invert_tx : 1; // 0 invert TX spreading sequence
- uint8_t chirp_invert_rx : 1; // 1 invert chip direction in RX mode
+ uint8_t chirp_invert_tx : 1; // 0 invert TX spreading sequence (default=1)
+ uint8_t chirp_invert_rx : 1; // 1 invert chip direction in RX mode (default=1)
uint8_t sync_detect_th : 1; // 2 require 6dB despread SNR during preamble
uint8_t invert_coef_phase : 1; // 3
uint8_t invert_coef_amp : 1; // 4
uint8_t quad_correction_en : 1; // 5 enable IQ compensation
- uint8_t invert_i_q : 1; // 6 RX invert
+ uint8_t invert_i_q : 1; // 6 RX invert (default=0)
uint8_t start_rambist : 1; // 7
} bits;
uint8_t octet;
} RegTest33_t;
+typedef union {
+ struct { // sx127x register 0x3b
+ uint8_t coarse_sync : 1; // 0 must be set to 1
+ uint8_t fine_sync : 1; // 1 must be clr to 0
+ uint8_t invert_timing_error_per_symbol : 1; // 2 set to !invert_i_q
+ uint8_t invert_freq_error : 1; // 3
+ uint8_t invert_delta_sampling : 1; // 4 must be set to 1
+ uint8_t reserved : 1; // 5 must be clr to 0
+ uint8_t invert_fast_timing : 1; // 6
+ uint8_t invert_carry_in : 1; // 7
+ } bits;
+ uint8_t octet;
+} RegDriftInvert_t;
+
+
//class SX127x_lora : public SX127x
class SX127x_lora {
public:
@@ -230,6 +246,13 @@
*/
int get_freq_error_Hz(void);
+
+ /** invert transmitted spectrum */
+ void invert_tx(bool);
+
+ /** invert spectrum on receiver */
+ void invert_rx(bool);
+
RegIrqFlags_t RegIrqFlags; // 0x12
uint8_t RegRxNbBytes; // 0x13
RegModemStatus_t RegModemStatus; // 0x18
@@ -244,6 +267,8 @@
uint8_t RegHopPeriod; // 0x24
RegModemConfig3_t RegModemConfig3; // 0x26
RegTest31_t RegTest31; // 0x31
+ RegTest33_t RegTest33; // 0x33
+ RegDriftInvert_t RegDriftInvert; // 0x3b
SX127x& m_xcvr;