The MPC5554DEMO platform HAL package is loaded automatically when eCos
is configured for an mpc5554demo target. It should
never be necessary to load this package explicitly. Unloading the
package should only happen as a side effect of switching target
The MPC5554DEMO platform HAL package supports three separate startup types:
This is the startup type which is normally used during application
development. The board has RedBoot programmed into flash at location
0x00020000 and boots from that location.
powerpc-eabi-gdb is then used to load a RAM
startup application into memory and debug it. It is assumed that the
hardware has already been initialized by RedBoot. By default the
application will use the eCos virtual vectors mechanism to obtain certain
services from RedBoot, including diagnostic output.
This startup type can be used for finished applications which will
be programmed into flash at location 0x00020000. The application will
be self-contained with no dependencies on services provided by other
software. eCos startup code will perform all necessary hardware
This startup type can be used for finished
applications which will be loaded into external RAM via a JTAG
debugger. The application will be self-contained with no dependencies on
services provided by other software. The JTAG debugger should initialize
the hardware enough to load the code into RAM, eCos startup code will
perform any further hardware initialization.
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
The MPC5554 microcontroller contains 2MiB of flash memory. The
CYGPKG_DEVS_FLASH_MPC5500 package contains all the
code necessary to support access to the flash. The MPC5554DEMO
platform HAL package contains definitions that customize the driver to
the MPC5554DEMO board.
By default, the system clock interrupts once every 10ms, corresponding
to a 100Hz clock. This can be changed by the configuration option
CYGNUM_HAL_RTC_DENOMINATOR which corresponds to the
clock frequency. Other clock-related settings are recalculated
automatically if the denominator is changed.
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 two flags specific to this port:
The powerpc-eabi-gcc compiler supports many
variants of the PowerPC architecture.
A -m option should be used to select the specific
variant in use. The MPC5554 is a Book E processor, and the current
tools do not have an option to select this processor directly
so instead we select a processor that is also Book E based and
which is supported: the MPC8540.
The PowerPC processor used in the MPC5554DEMO boards does not have a
floating point unit. Therefore it is necessary to translate
any floating point operations into software emulation. This
option tells the compiler to do that.