Zephyr Hardware I/O
Interface with the physical world using Zephyr's standardized driver models and hardware abstraction layers.
Core Workflows
1. Sensor Subsystem
Interact with various sensors using a uniform API for data fetching and decoding.
- Reference: sensors.md
- Key Tools:
sensor_sample_fetch,sensor_channel_get,struct sensor_value.
2. Pinctrl & GPIO
Manage pin multiplexing, electrical configuration, and basic digital input/output.
- Reference: pinctrl_gpio.md
- Key Tools:
pinctrl,gpio_dt_spec,GPIO_DT_SPEC_GET.
3. SoC Configuration
Tune chip-level parameters and manage hardware across multiple board variants.
- Reference: soc_config.md
- Key Tools:
Kconfig,soc_common.dtsi, SoC-level overlays.
Quick Start (Sensor Polling)
c#include <zephyr/drivers/sensor.h> const struct device *temp_sensor = DEVICE_DT_GET(DT_ALIAS(ambient_temp0)); struct sensor_value val; void poll_sensor(void) { if (sensor_sample_fetch(temp_sensor) == 0) { sensor_channel_get(temp_sensor, SENSOR_CHAN_AMBIENT_TEMP, &val); } }
Professional Patterns (Hardware Engineering)
- Safe GPIO: Always use
gpio_dt_specto ensure polarity and pin number are automatically handled by the driver. - Background Sampling: Never poll sensors in high-priority threads; use a background work queue. See kernel-services for work-queue patterns.
- Deferred Pinctrl: Define pin states in a shared
.dtsito simplify multi-revision hardware support.
Automation Tools
- gpio_alias_check.py: Detect duplicate alias entries across DTS/overlay files.
Examples & Templates
- sensor_poll_template.c: Starter polling function with readiness/error checks.
Validation Checklist
- Sensor device nodes resolve correctly and
DEVICE_DT_GET(...)targets are ready at runtime. - GPIO and pinctrl states match the intended board schematic and polarity rules.
- Sensor sampling path returns stable values with expected units/scaling.
- Background acquisition does not block high-priority or interrupt-critical code paths.
Resources
- References:
sensors.md: Reading data, channels, and triggers.pinctrl_gpio.md: Pin multiplexing and GPIO specs.soc_config.md: Multi-variant SoC configuration.
- Scripts:
gpio_alias_check.py: Alias duplication checker for DTS/overlay sets.
- Assets:
sensor_poll_template.c: Polling loop starter template.
