Devices

Overview

The device folder in the root of embARC contains the necessary software APIs and implementations for common device IP and external peripheral drivers. The device layer consists of the following components:

  • Device HAL: a device hardware abstraction layer including WNIC (Wireless Network Interface Controller), UART (Universal Asynchronous Receiver/Transmitter), SPI (Serial Peripheral Interface), IIC (Inter- Integrated Circuit), I2S (Inter-IC Sound), GPIO (General Purpose Input Output) and SDIO (Secure Digital Input and Output).
  • IP Driver Implementation: device driver implementations based on the above device HAL, including DesignWare IP implementations of UART, IIC, SPI, GPIO and SDIO devices and Designware ARC Subsystem IP implementation.
  • Peripheral Driver Implementation: peripheral driver implementations such as flash, sensors and PMOD modules.
embARC Device HAL

Device HAL

The Device HAL provides abstraction for the following devices:

These *.h files provide abstraction APIs and macros that require corresponding implementations. embARC OSP provides the device implementations in device/ip/designware, device/ip/subsystem, device/peripheral, and board/xxxx/drivers.

Different device features are abstracted in the device HAL, such as UART, IIC, and SPI. Object-oriented concepts are adopted to provide common device operation APIs and device access APIs.

IP Drivers

The IP drivers are placed in device/ip folder. Currently, the following Designware IP drivers are supported:

  • GPIO
  • UART
  • I2C
  • SPI
  • I2S
  • SDIO

and the follong Designware ARC subsystem IP drivers are supported:

  • GPIO
  • UART
  • I2C master
  • SPI master
  • I2S master

In the future, more Designware IP drivers will be added, e.g., timer, PWM, ethernet

Not limited to Designware IP drivers, other IP drivers can be easily supported which can take Designware IP drivers as a reference.

Driver Instantiation

The device drivers will be instantiated in board BSP based on specific hardware information. Taking EMSK board as an example, its drivers’ instantiation is located in board/emsk/drivers/ip/designware. Different instantiations of same type driver will be differentiated through ID.

There are 3 UARTs in EMSK, their instantiations are in dw_uart_obj.c and ID allocations & other related definitions are in dw_uart_obj.h.

External Peripheral Drivers

The external peripheral drivers are placed in device/peripheral folder. embARC OSP already include some common external peripheral drivers, especially PMOD modules.

  • MRF24J40, a 802.15.4 based transceiver.
  • AD7991, a I2C interface AD converter.
  • HM1X, a UART-BLE module.
  • W25QXX, a SPI Flash chip.
  • ADT7420, a I2C interface temperature sensor.
  • TCN75, a I2C interface temperature sensor.
  • MRF24G, a SPI WiFi module.
  • RW009, a SPI WiFi module.
  • RN4020, a UART-BLE module.
  • MPU9250, a 9D IMU module.