HAL

Collaboration diagram for HAL:

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Detailed Description

Hardware Abstraction Layer.

Under ChibiOS/RT the set of the various device driver interfaces is called the HAL subsystem: Hardware Abstraction Layer. The HAL is the abstract interface between ChibiOS/RT application and hardware.

HAL Device Drivers Architecture

A device driver is usually split in two layers:

• High Level Device Driver (HLD). This layer contains the definitions of the driver's APIs and the platform independent part of the driver.
  An HLD is composed by two files:
  • <driver>.c, the HLD implementation file. This file must be included in the Makefile in order to use the driver.
  • <driver>.h, the HLD header file. This file is implicitly included by the HAL header file hal.h.
• Low Level Device Driver (LLD). This layer contains the platform dependent part of the driver.
  A LLD is composed by two files:
  • <driver>_lld.c, the LLD implementation file. This file must be included in the Makefile in order to use the driver.
  • <driver>_lld.h, the LLD header file. This file is implicitly included by the HLD header file.
  The LLD may be not present in those drivers that do not access the hardware directly but through other device drivers, as example the MMC_SPI driver uses the SPI and PAL drivers in order to implement its functionalities.

Diagram

Modules
	ADC Driver
	Generic ADC Driver.
	CAN Driver
	Generic CAN Driver.
	EXT Driver
	Generic EXT Driver.
	GPT Driver
	Generic GPT Driver.
	HAL Driver
	Hardware Abstraction Layer.
	I2C Driver
	Generic I2C Driver.
	I2S Driver
	Generic I2S Driver.
	ICU Driver
	Generic ICU Driver.
	Abstract I/O Block Device
	Abstract I/O Channel
	MAC Driver
	Generic MAC driver.
	MMC over SPI Driver
	Generic MMC driver.
	MMC/SD Block Device
	PAL Driver
	I/O Ports Abstraction Layer.
	PWM Driver
	Generic PWM Driver.
	RTC Driver
	Real Time Clock Abstraction Layer.
	SDC Driver
	Generic SD Card Driver.
	Serial Driver
	Generic Serial Driver.
	Serial over USB Driver
	Serial over USB Driver.
	SPI Driver
	Generic SPI Driver.
	Time Measurement Driver
	Time Measurement unit.
	UART Driver
	Generic UART Driver.
	USB Driver
	Generic USB Driver.
	Configuration
	HAL Configuration.