Configuration

Configuration
	Chapter 335. MIPS Malta Board Support

Overview

The Malta platform HAL package is loaded automatically when eCos is configured for a malta 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.

Target Selection

The exact processor type is determined by the target selected during configuration. The following targets are currently supported:

malta_mips32_4kc: Board fitted with 4Kc core card.
malta_mips32_4kec: Board fitted with 4KEc core card.
malta_mips32_5kc: Board fitted with 5Kc core card. This will only support a RedBoot configuration.

Startup

The Malta platform HAL package supports two 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. mipsisa32-elf-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 0xbe000000. 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 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 Malta board contains two 16 bit Intel 28F160 flash devices arranged in parallel to form a 32 bit wide interface. The CYGPKG_DEVS_FLASH_INTEL_28FXXX package contains all the code necessary to support these parts and the CYGPKG_DEVS_FLASH_MALTA package contains definitions that customize the driver to the Malta board.

Ethernet Driver

The Malta board contains an AMD Am79C973 PCnet ethernet MAC. The CYGPKG_DEVS_ETH_AMD_PCNET package contains all the code necessary to support this device and the CYGPKG_DEVS_ETH_MIPS_MIPS32_MALTA package contains definitions that customize the driver to the Malta 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.

-mips32: The mipsisa32-elf-gcc compiler supports many variants of the MIPS architecture. A -m option should be used to select the specific variant in use, and with current tools -mips32 is the correct option for the 4Kc and 4KEc processors.
-mips64: If the board is populated with a 5Kc processor, then RedBoot may be built with 64 bit support. In that case, stand-alone applications may be built with the -mips64 option. This option is not currently supported by eCos applications.


Setup		The HAL Port

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