HAL Port — Implementation Details
This documentation explains how the eCos HAL specification has been mapped onto the M5272C3 hardware, and shold be read in conjunction with that specification. The M5272C3 platform HAL package complements the M68K architectural HAL, the MCFxxxx variant HAL, and the MCF5272 processor HAL. It provides functionality which is specific to the target board.
Following a hard or soft reset the HAL will initialize or reinitialize most of the on-chip peripherals. There is an exception for RAM startup applications which depend on a ROM monitor for certain services: the UARTs and the ethernet device will not be reinitialized because they may be in use by RedBoot for communication with the host.
For a ROM or ROMFFE startup the HAL will perform additional
initialization, setting up the external DRAM and programming the
various internal registers. The values used for most of these
registers are configurable. Full
details can be found in the exported headers
The platform HAL provides configuration options for the eCos system clock. This always uses the hardware timer 3, which should not be used directly by application code. The gprof-based profiling code uses timer 2, so that is only available when not profiling. Timers 0 and 1 are never used by eCos so application code is free to manipulate these as required. The actual HAL macros for managing the clock are provided by the MCF5272 processor HAL. The specific numbers used are a characteristic of the platform because they depend on the processor speed.
The M5272C3 platform HAL does not affect the implementation of other parts of the eCos HAL specification. The MCF5272 processor HAL, the MCFxxxx variant HAL, and the M68K architectural HAL documentation should be consulted for further details.
The platform HAL package also provides a flash driver for the off-chip
AMD AM29PL160C flash chip. This driver is inactive by default, and
only becomes active if the configuration includes the generic flash
When building RedBoot with the Robust Boot Loader package
CYGPKG_RBL, the platform HAL provides a macro for
the rbl condboot command. If the INT6 button
is pressed when rbl condboot executes then the
boot will be aborted, otherwise it will proceed normally.
|2021-10-22||Open Publication License|