Overview

The MCIMX25X platform HAL package is loaded automatically when eCos is configured for the mcimx25x target. It should never be necessary to load this package explicitly. Unloading the package should only happen as a side effect of switching target hardware.

Startup

The platform HAL package supports three separate startup types:

RedBoot and Virtual Vectors

If the application is intended to act as a ROM monitor, providing services for other applications, then the configuration option CYGSEM_HAL_ROM_MONITOR should be set. Typically this option is set only when building RedBoot.

If the application is supposed to make use of services provided by a ROM monitor, via the eCos virtual vector mechanism, then the configuration option CYGSEM_HAL_USE_ROM_MONITOR should be set. By default this option is enabled when building for a RAM startup, disabled otherwise. It can be manually disabled for a RAM startup, making the application self-contained, as a testing step before switching to ROM startup.

If the application does not rely on a ROM monitor for diagnostic services then the serial port will be claimed for HAL diagnostics.

Flash Driver

The board contains an 2Mbyte Macronix MX25L1605D SPI serial NOR flash device. The CYGPKG_DEVS_FLASH_SPI_M25PXX package contains all the code necessary to support this part and the platform HAL package contains definitions that customize the driver to the board. This driver is not active until the generic Flash support package, CYGPKG_IO_FLASH, is included in the configuration.

This driver is capable of supporting the JFFS2 filesystem. However, note that the SPI interface means that this file system has reduced bandwidth and increased latency compared with other implementations. All that is required to enable the support is to include the filesystem (CYGPKG_FS_JFFS2) and any of its package dependencies (including CYGPKG_IO_FILEIO and CYGPKG_LINUX_COMPAT) together with the flash infrastructure (CYGPKG_IO_FLASH).

Ethernet Driver

The board uses the internal FEC Ethernet device attached to an external Texas Instruments DP83640 PHY. The CYGPKG_DEVS_ETH_FREESCALE_ENET package contains all the code necessary to support this device and the platform HAL package contains definitions that customize the driver to the board. This driver is not active until the generic Ethernet support package, CYGPKG_IO_ETH_DRIVERS, is included in the configuration.

Watchdog Driver

The board uses the i.MXxx internal watchdog. The CYGPKG_DEVICES_WATCHDOG_ARM_IMX package contains all the code necessary to support this device. Within that package the CYGNUM_DEVS_WATCHDOG_ARM_IMX_DESIRED_TIMEOUT_MS configuration option controls the watchdog timeout, and by default will force a reset of the board upon timeout. This driver is not active until the generic watchdog device support package, CYGPKG_IO_WATCHDOG, is included in the configuration.

UART Serial Driver

The board uses the i.MXxx internal UART serial support as described in the i.MXxx processor HAL documentation. Only one serial connector is available on the board, which is connected to UART1. This connector has the RTS/CTS hardware flow control lines connected in addition to the data lines.

ADC Driver

ADC support is provided by the CYGPKG_DEVS_ADC_ARM_TSC package. Only ADC inputs INAUX0, INAUX1 and INAUX2 are supported at present. In addition to the TSC ADC device, this driver uses GPT1 to provide the sample rate clock. Application code should avoid using this timer if the ADC is to be used. This driver is only active if the generic ADC support package, CYGPKG_IO_ADC, is included in the configuration.

LCD Driver

LCD support is provided by the CYGPKG_DEVS_FRAMEBUF_ARM_IMX package. It supports a single frame buffer format, 640 by 480 pixels, 16 bits per pixel true colour. The frame buffer is placed at a fixed address in memory at 0x83F00000. This driver is only active if the generic framebuffer support package, CYGPKG_IO_FRAMEBUF, is included in the configuration.

Compiler Flags

The platform HAL defines the default compiler and linker flags for all packages, although it is possible to override these on a per-package basis. Most of the flags used are the same as for other architectures supported by eCos. There are just three flags specific to this port: