Configuration Reference
All compile-time configuration is defined in include/config.h.
Hardware Pins (TTGO LoRa32 V2.1)
LoRa SPI (SX1276)
| Define |
GPIO |
Function |
LORA_SCK |
5 |
SPI Clock |
LORA_MISO |
19 |
SPI MISO |
LORA_MOSI |
27 |
SPI MOSI |
LORA_SS |
18 |
SPI Chip Select |
LORA_RESET |
14 |
Radio Reset |
LORA_DIO0 |
26 |
Radio IRQ (DIO0) |
OLED Display (SSD1306, I2C)
| Define |
GPIO |
Function |
OLED_SDA |
21 |
I2C Data |
OLED_SCL |
22 |
I2C Clock |
OLED_RST |
16 |
Display Reset |
Other
| Define |
GPIO |
Function |
BUZZER_PIN |
4 |
Buzzer output (active high) |
BATTERY_ADC_PIN |
35 |
VBAT through a 100k/100k divider (ADC1_CH7) |
Battery Monitoring
The battery icon in the top-right corner of the OLED header shows 4 segments, one per started 25 %.
Below BATTERY_LOW_PERCENT one segment blinks. The voltage is read with analogReadMilliVolts(), averaged,
EMA-filtered and mapped to a percentage with a Li-Ion discharge curve (firmware/shared/battery/battery_level.h).
The LoRa32 cannot detect charging or a missing cell: without a battery, the charger voltage reads as a full cell.
| Define |
Value |
Description |
BATTERY_SCALE_FACTOR |
2.0 |
Divider ratio (VBAT = ADC × factor) |
BATTERY_ADC_SAMPLES |
16 |
ADC conversions averaged per sample |
BATTERY_SAMPLE_INTERVAL_MS |
1000 ms |
Sample period (in networkTask, Core 0) |
BATTERY_LOW_PERCENT |
10 |
Icon blinks below this level |
BATTERY_BLINK_INTERVAL_MS |
500 ms |
Low-battery blink half-period |
LoRa Radio Parameters
| Define |
Value |
Description |
LORA_FREQUENCY |
433700000 (433.7 MHz) |
Carrier frequency |
LORA_SPREADING_FACTOR |
7 |
SF7 — fastest data rate |
LORA_BANDWIDTH |
500E3 (500 kHz) |
Signal bandwidth |
LORA_CODING_RATE |
5 |
4/5 coding rate |
LORA_TX_POWER |
20 |
Transmit power in dBm |
LORA_SYNC_WORD |
0x12 |
Network sync word |
Preamble length is set to 12 symbols. Hardware CRC is enabled.
Protocol Constants
| Define |
Value |
Description |
MAX_PACKET_SIZE |
512 |
Maximum raw packet buffer |
HEADER_SIZE |
4 |
LoRa packet header size (bytes) |
MAX_DATA_SIZE |
508 |
Max payload per packet |
MAX_MESSAGE_BUFFER |
16384 |
16 KB reassembly buffer |
Timing
| Define |
Value |
Description |
DISPLAY_UPDATE_INTERVAL |
500 ms |
OLED refresh rate |
PACKET_TIMEOUT |
5000 ms |
Timeout for incomplete multi-packet messages |
BUZZER_PULSE_US |
1000 µs |
Buzzer pulse duration per beep |
WiFi Access Point
| Define |
Value |
Description |
WIFI_SSID |
OSS-LoRa-RX |
AP network name |
WIFI_PASSWORD |
lora123456 |
AP password (WPA2) |
WIFI_CHANNEL |
1 |
WiFi channel |
WIFI_MAX_CONNECTIONS |
4 |
Max simultaneous WiFi clients |
NTRIP Server
| Define |
Value |
Description |
NTRIP_PORT |
2101 |
TCP listen port |
NTRIP_MOUNT_POINT |
LORA |
NTRIP mount point name |
NTRIP_MAX_CLIENTS |
4 |
Max concurrent NTRIP streams |
RTCM_BUFFER_SIZE |
8192 |
Circular buffer for RTCM parsing (bytes) |
Dual-Core (FreeRTOS)
| Define |
Value |
Description |
LORA_CORE |
1 |
CPU core for LoRa reception |
NETWORK_CORE |
0 |
CPU core for WiFi/NTRIP/display |
LORA_TASK_STACK |
8192 |
Stack size for LoRa task (bytes) |
NETWORK_TASK_STACK |
8192 |
Stack size for network task (bytes) |
LORA_TASK_PRIORITY |
2 |
FreeRTOS priority (higher = more urgent) |
NETWORK_TASK_PRIORITY |
1 |
FreeRTOS priority |
RTCM_QUEUE_SIZE |
16 |
Max RTCM messages queued between cores |
Debug
| Define |
Value |
Description |
ENABLE_UART_LOGGING |
true |
Set to false to disable all Serial output |
Serial baud rate: 115200 (configured in debug.cpp).
Target environment: ttgo-lora32-v21
Dependencies (from platformio.ini):
thingpulse/ESP8266 and ESP32 OLED driver for SSD1306 displays@^4.4.0sandeepmistry/LoRa@^0.8.0