This document introduces a digital compass reference design with SiRFstar2t GPS chip set, which combines Honeywell magnetic sensor products and SiRF technology for pedestrian navigation and vehicle remote communication systems.
The AN219 application note introduces a digital‑compass reference design that merges a SiRFstar2t GPS processor with Honeywell magnetic sensors, MEMS accelerometers and a host micro‑processor. It explains how the solution enables reliable navigation for handheld pedestrian devices and vehicle remote‑communication systems, even when GPS signals are temporarily blocked.
The document details the circuit architecture, including the HMC6042 dual‑axis magnetic sensor, 14‑bit ADC inputs, reset/set pulse generation, and required passive components. It also covers firmware processing, calibration methods, and accuracy requirements for indoor navigation and vehicle applications. This manual is written in Chinese.
| ADC resolution for sensor inputs | 14‑bit |
|---|---|
| Magnetic field range (max before saturation) | ±20 Gauss |
| Reset/Set pulse width | 1‑2 µs |
| Capacitor for pulse timing | 0.22 µF (C2) |
The design uses the Honeywell HMC6042 dual‑axis magnetic sensor.
The SiRFstar2t IC provides two 14‑bit ADC inputs for external sensors.
The reset/set pulse lasts about 1‑2 µs.