eCos® and eCosPro® Reference Manual
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Configuration

Name

Configuration -- Platform-specific Configuration Options

Overview

The ADS512101 platform HAL package is loaded automatically when eCos is configured for an ads512101 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 ADS512101 platform HAL package supports four separate startup types:

RAM: This is the startup type which is normally used during application development. The board has ROMRAM RedBoot running from 0x00000000 and applications will be loaded from 0x00100000. 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.
ROM: This startup type can be used for finished applications which will be programmed into flash at location 0xFFF00000. The application will be self-contained with no dependencies on services provided by other software. eCos startup code will perform all necessary hardware initialization.
ROMRAM: This startup type can be used for finished applications which will be programmed into flash at location 0xFFF00000. The first thing the application does is to relocate itself to RAM at location 0x00000000. The application will be self-contained with no dependencies on services provided by other software. eCos startup code will perform all necessary hardware initialization.
JTAG: 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 diagnostics.

Flash Driver

The ADS512101 board contains 64MiB of flash memory. The CYGPKG_DEVS_FLASH_AMD_AM29XXXXX_V2 package contains all the code necessary to support access to the flash. The ADS512101 platform HAL package contains definitions that customize the driver to the ADS512101 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.

Ethernet Driver

The ADS512101 board uses the MPC5121e's internal FEC ethernet device attached to an external PHY. The CYGPKG_DEVS_ETH_POWERPC_FEC package contains all the code necessary to support this device. The CYGPKG_DEVS_ETH_POWERPC_ADS512101 package contains definitions that customize the driver to the ADS512101 board. This driver is not active until the generic Ethernet support package, CYGPKG_IO_ETH_DRIVERS, is included in the configuration.

RTC Driver

The ADS512101 board uses an ST M41T662 I2C Real Time Clock. The CYGPKG_DEVICES_WALLCLOCK_ST_M41TXX package contains all the code necessary to support this device. This device also needs the CYGPKG_IO_I2C package to be loaded. This driver is not active until the generic wallclock device support package, CYGPKG_IO_WALLCLOCK, is included in the configuration.

Watchdog Driver

The ADS512101 board uses the MPC5121e's internal watchdog support. The CYGPKG_DEVICES_WATCHDOG_MPC512X package contains all the code necessary to support this device. Within that package the CYGNUM_DEVICES_WATCHDOG_POWERPC_MPC512X_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 ADS512101 board uses the MPC5121e's Programmable Serial Controllers (PSC's) configured for UART mode. Two serial UART adaptors are available on the board. However, only PSC3 is attached to a ( pin D-Sub connector. PSC4 is connected to header P8.

I2C Driver

The MPC512X HAL contains a driver for the I2C busses on the board. There are several devices attached to the busses, of which, only the RTC on Bus0 is actually used bt eCos.

CAN Driver

The MPC512X contains four Freescale MSCAN devices, although only one of these is brought out to an external connector. The package CYGPKG_DEVS_CAN_MSCAN is a general driver for the MSCAN, and the package CYGPKG_DEVS_CAN_ADS512101 configures this for the ADS512101 platform.

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 one flag specific to this port:

-mcpu=e300c3: 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 MPC5121e is a e300c4 processor, and the current tools do not have an option to select this processor directly so instead we select a processor that is identical as far as the compiler is concerned, the e300c3.

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