The IQ80321 platform HAL package is loaded automatically when eCos is
configured for a iq80321 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 IQ80321 platform HAL package supports two separate startup types:
RAM
This is the startup type which is normally used during application
development. The board has RedBoot programmed into flash
and boots into that initially.
arm-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.
ROM
This startup type can be used for finished applications which will
be programmed into flash at physical address 0xF0000000. The application will
be self-contained with no dependencies on services provided by other
software. eCos startup code will perform all necessary 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 required 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
RAM startup, disabled otherwise. It can be manually disabled for 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 IQ80321 board contains an 8MB Intel StrataFlash
flash device.
The
CYGPKG_DEVS_FLASH_STRATA package contains all the
code necessary to support these parts and the
CYGPKG_DEVS_FLASH_IQ80321 package contains
definitions that customize the driver to the IQ80321 board.
Ethernet Driver
The IQ80321 board contains an Intel i82544 ethernet controller.
The CYGPKG_DEVS_ETH_INTEL_I82544
package contains all the code necessary to support this device and the
CYGPKG_DEVS_ETH_ARM_IQ80321 package contains
definitions that customize the driver to the IQ80321 board.
System Clock
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.
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 is just one flag specific to this port:
-mcpu=xscale
The arm-eabi-gcc compiler supports many
variants of the ARM architecture.
A -m option should be used to select the specific
variant in use, and with current tools -mcpu=xscale is the
correct option for the XScale CPU on the IOP321.