Firmware Specifications
Firmware Specifications
Section titled “Firmware Specifications”Complete technical specifications for the Multiflexmeter 3.7.0 firmware platform.
Firmware Information
Section titled “Firmware Information”| Specification | Value |
|---|---|
| Version | 0.0.0 (Development) |
| Build System | PlatformIO |
| Framework | Arduino Core |
| Language | C++ (C++11) |
| Compiler | AVR-GCC |
| Flash Usage | ~30-35 KB (varies by board) |
| RAM Usage | ~2-4 KB (varies by board) |
| EEPROM Usage | 64 bytes (configuration) |
Core Libraries
Section titled “Core Libraries”| Library | Version | Purpose | Size Impact |
|---|---|---|---|
| MCCI Arduino LoRaWAN | ^0.9.2 | LoRaWAN protocol stack | ~30KB flash |
| MedianFilter | Local | Sensor data filtering | <1KB flash |
| Adafruit SleepyDog | ^1.6.4 | Declared dependency (unused) | 0KB |
Communication Protocols
Section titled “Communication Protocols”LoRaWAN Configuration
Section titled “LoRaWAN Configuration”| Parameter | Value |
|---|---|
| Region | EU868 |
| Class | Class A |
| Activation | OTAA (Over-The-Air) |
| Data Rate | DR0-DR7 (SF12-SF7) |
| TX Power | 14 dBm default |
| Duty Cycle | EU regulations compliant |
| Port | 1 (application data) |
SMBus/I²C Interface
Section titled “SMBus/I²C Interface”| Parameter | Value |
|---|---|
| Protocol | SMBus/I²C |
| Clock Speed | 100 kHz (standard mode) |
| Slave Address | 0x36 |
| Data Format | 16-bit big-endian |
| Commands | Read sensor data |
EEPROM Configuration Structure
Section titled “EEPROM Configuration Structure”Configuration Layout (64 bytes)
Section titled “Configuration Layout (64 bytes)”| Offset | Size | Field | Description |
|---|---|---|---|
| 0x00 | 8 bytes | deveui | Device EUI for LoRaWAN |
| 0x08 | 8 bytes | appeui | Application EUI |
| 0x10 | 16 bytes | appkey | Application Key |
| 0x20 | 4 bytes | devaddr | Device Address |
| 0x24 | 16 bytes | nwkskey | Network Session Key |
| 0x34 | 16 bytes | appskey | Application Session Key |
| 0x44 | 4 bytes | netid | Network ID |
| 0x48 | 4 bytes | seqnoUp | Uplink sequence number |
| 0x4C | 4 bytes | seqnoDn | Downlink sequence number |
| 0x50 | 1 byte | version | Configuration version |
| 0x51 | 15 bytes | Reserved | Future use |
Version Encoding
Section titled “Version Encoding”// Version format: 0xMMmmpp (Major.minor.patch)#define CONFIG_VERSION_MAJOR 3#define CONFIG_VERSION_MINOR 7#define CONFIG_VERSION_PATCH 0// Results in version byte: 0x37 (3.7.0)Build Configurations
Section titled “Build Configurations”Board Variants
Section titled “Board Variants”| Board ID | MCU | Flash | RAM | Clock | Core |
|---|---|---|---|---|---|
mfm_v3_m1284p | ATmega1284P | 128KB | 16KB | 8MHz | MightyCore |
mfm_v3 | ATmega328P | 32KB | 2KB | 8MHz | MiniCore |
Compiler Flags
Section titled “Compiler Flags”build_flags = -DCFG_eu868=1 -DCFG_sx1276_radio=1 -DARDUINO_LMIC_PROJECT_CONFIG_H_SUPPRESS -DSERIAL_BAUD=115200Power Consumption
Section titled “Power Consumption”| Mode | Current Draw | Duration | Notes |
|---|---|---|---|
| Active | ~50-100mA | <1 second | During transmission |
| Sleep | ~5-10µA | 95%+ of time | LMIC power management |
| Sensor Read | ~20-30mA | <100ms | I²C communication |
Timing Specifications
Section titled “Timing Specifications”| Event | Interval | Variation | Notes |
|---|---|---|---|
| Sensor Perform → Read | 10 seconds | Fixed | MEASUREMENT_SEND_DELAY_AFTER_PERFORM_S |
| Join → Version Ping | 45 seconds | Fixed | MEASUREMENT_DELAY_AFTER_PING_S |
| Measurement Interval | 20-4270 seconds | Configurable | From EEPROM, bounds checked |
| Reset Delay | 5 seconds | Fixed | After 0xDEAD command |
| LoRaWAN TX | Duty cycle limited | EU868 regulations | Max 1% duty cycle |
| Watchdog Reset | 8 seconds | Hardware timer | Safety mechanism |
Memory Layout
Section titled “Memory Layout”Flash Memory Usage
Section titled “Flash Memory Usage”| Section | Size | Description |
|---|---|---|
| Bootloader | ~2KB | Arduino bootloader |
| Application | ~30-35KB | Main firmware |
| LMIC Library | ~25KB | LoRaWAN stack |
| Arduino Core | ~5KB | Hardware abstraction |
| Free Space | ~60-90KB | Available for expansion |
RAM Usage
Section titled “RAM Usage”| Section | Size | Description |
|---|---|---|
| LMIC Stack | ~1.5KB | LoRaWAN buffers |
| Application | ~0.5-1KB | Variables and buffers |
| Arduino Core | ~0.5KB | System overhead |
| Free Stack | Remaining | Available for local variables |
API Interface
Section titled “API Interface”Main Functions
Section titled “Main Functions”| Function | Purpose | Call Frequency |
|---|---|---|
setup() | Board, sensor, LMIC initialization | Once at boot |
loop() | LMIC job scheduler only | Continuous (os_runloop_once()) |
onEvent() | LMIC event handler | On LoRaWAN events |
job_performMeasurements() | Trigger sensor measurement | LMIC scheduled |
job_fetchAndSend() | Read and transmit sensor data | After 10s delay |
job_pingVersion() | Send version after join | After join completion |
scheduleNextMeasurement() | Calculate next measurement time | After transmission |
processDownlink() | Handle downlink commands | On RX data |
Job Functions
Section titled “Job Functions”// Actual job functions used in firmwarevoid job_pingVersion(osjob_t *job); // Send version info after joinvoid job_performMeasurements(osjob_t *job); // Start sensor measurementvoid job_fetchAndSend(osjob_t *job); // Read sensor and transmitvoid job_reset(osjob_t *job); // Device reset via watchdogvoid job_error(osjob_t *job); // Error state (infinite loop)Compatibility
Section titled “Compatibility”Arduino IDE Compatibility
Section titled “Arduino IDE Compatibility”| IDE Version | Support | Notes |
|---|---|---|
| Arduino IDE 1.8.x | ✅ Yes | Recommended |
| Arduino IDE 2.x | ✅ Yes | Modern interface |
| PlatformIO | ✅ Yes | Primary development |
Core Dependencies
Section titled “Core Dependencies”| Core | Board | Compatibility |
|---|---|---|
| MightyCore | ATmega1284P | Required for mfm_v3_m1284p |
| MiniCore | ATmega328P | Required for mfm_v3 |