Jacob Board Code

Jacob is the LoRa uplink board. It receives framed TelemetryData from Spencer over I2C (Wire1, slave 0x08), reassembles packets, optionally schedules RFM95 transmissions in a PPS-aligned window using GPS unix time, and logs diagnostics on Serial1.

Debug guide

Status LED (Teensy)

Pin	Behavior
7 (LED_PIN)	Double short pulse: a full length-prefixed telemetry packet was reassembled from I2C (markTelemetryPacketReady). Single long pulse: LoRa TX finished successfully (waitPacketSent). Toggle on PPS when a LoRa TX window is scheduled from unix epoch + slot timing. At end of setup(), the LED is driven HIGH as a “ready” indication.

UART — Serial1

Firmware calls Serial1.begin(115200) in setup(). All Serial1.print / println diagnostics (I2C assembly, PPS scheduling, LoRa send, optional verbose I2C traces) use this port.

Teensy 4.x and a 3.3 V USB–UART adapter

Adapter wire	Teensy connection
GND	GND (common ground)
RX (USB–UART IC receive)	Pin 1 — Teensy TX1 (MCU transmits debug text here)
TX (USB–UART IC transmit)	Pin 0 — Teensy RX1 (optional: MCU input if you send commands)

Use 115200 baud in your serial terminal. Do not connect 5 V TTL UART lines directly to Teensy pins; use 3.3 V logic levels only.

Other useful pins (reference)

• PPS: pin 8 (input) — GPS pulse-per-second for timing.
• LoRa (defaults in JacobBoardCode.ino):
  • CS → pin 10
  • RST → pin 2
  • DIO0 / IRQ → pin 3 (RFM95_INT) — must reach the SX127x DIO0 pad so RadioHead gets TX done. If this wire is wrong or missing, firmware used to hang forever after rf95.send(); it now times out after a few seconds, prints an error, and calls setModeIdle().

LoRa “freeze” right after rf95.send()

RadioHead blocks in waitPacketSent() until the RFM95 DIO0 interrupt fires (pin 3 on this sketch). If the console prints rf95.send(), len=... and then nothing until a timeout message:

1. Confirm DIO0 on the module is wired to Teensy pin 3 (not DIO1-only boards used as if they were DIO0).
2. Confirm SPI (MOSI/MISO/SCK + CS 10) and 3.3 V to the module.
3. Keep USB–UART RX on pin 1 only; accidentally routing UART onto the LoRa IRQ pin can break interrupts.

Related repos

• TelemetryCommon — shared TelemetryData.h / LoRaTelemetryPayload layout.
• SpencerBoardCode — telemetry source and telemetry_packet_viewer.py for SD logs.