eCosPro® Reference Manual
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# Configuration

## Name

Configuration -- Platform-specific Configuration Options

## Overview

The AT91SAM9263-EK platform HAL package is loaded automatically when eCos is configured for the sam9263ek 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 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 DataFlash. The application will be self-contained with no dependencies on services provided by other software. eCos startup code will perform all necessary hardware initialization. This startup type can also be used for applications loaded via JTAG.

## 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 board has an SD/MMC/DataFlash socket into which a dataflash card may be inserted. The CYGPKG_DEVS_FLASH_ATMEL_DATAFLASH package contains all the code necessary to support this part and the platform HAL package contains definitions that customize the driver to the AT91SAM9263-EK board. This driver is not active until the generic Flash support package, CYGPKG_IO_FLASH, is included in the configuration.

## Ethernet Driver

The AT91SAM9263-EK board uses the AT91SAM9263's internal EMAC ethernet device attached to an external Davicom DM9161A PHY. The CYGPKG_DEVS_ETH_ARM_AT91 package contains all the code necessary to support this device and the platform HAL package contains definitions that customize the driver to the AT91SAM9263-EK board. This driver is not active until the generic Ethernet support package, CYGPKG_IO_ETH_DRIVERS, is included in the configuration.

## RTC Driver

The AT91SAM9263-EK board uses the AT91SAM9263's internal RTTC support. The CYGPKG_DEVICES_WALLCLOCK_ARM_AT91RTTC package contains all the code necessary to support this device. This driver is not active until the generic wallclock device support package, CYGPKG_IO_WALLCLOCK, is included in the configuration.

## Watchdog Driver

The AT91SAM9263-EK board uses the AT91SAM9263's internal watchdog support. The CYGPKG_DEVICES_WATCHDOG_ARM_AT91WDTC package contains all the code necessary to support this device. Within that package the CYGNUM_DEVS_WATCHDOG_ARM_AT91WDTC_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.

Warning
The ATSAM926x processor will boot with watchdog support enabled, and the watchdog configuration is write-once. That is, if it is disabled, it cannot be re-enabled. Due to its nature, RedBoot disables the watchdog when it starts so any eCos applications with watchdog support enabled that are run by RedBoot will not function correctly.

## USART Serial Driver

The AT91SAM9263-EK board uses the AT91SAM9263's internal USART serial support as described in the SAM9 processor HAL documentation. Two serial ports are available: the serial debug port which is mapped to virtual vector channel 0 in the HAL diagnostic driver or "`/dev/dbg`" in the interrupt-driven driver; and USART 0 which is mapped to virtual vector channel 1 and "`/dev/ser0`". The debug port is two wires only. but USART 0 supports RTS/CTS.

## MCI Driver

As the SAM9 MCI driver is part of the SAM9 HAL, nothing is required to load it. Similarly the MMC/SD bus driver layer (CYGPKG_DEVS_DISK_MMC) is automatically included as part of the hardware-specific configuration for this target. All that is required to enable the support is to include the generic disk I/O infrastructure package (CYGPKG_IO_DISK), along with the intended filesystem, typically, the FAT filesystem (CYGPKG_FS_FAT) and any of its package dependencies (including CYGPKG_LIBC_STRING and CYGPKG_LINUX_COMPAT for FAT).

Various options can be used to control specific aspects of the SAM9 MCI driver. Consult the SAM9 HAL documentation for information on its configuration. The option CYGHWR_HAL_ARM_ARM9_SAM9_SAM9263_MCI controls which of the two MCI interfaces will be used by the driver.

On this target, it is not possible to detect from the MMC/SD socket whether cards have been inserted or removed. Thus the disk I/O layer's removeable media support will not detect when cards have been inserted or removed, and therefore the only way to detect if a card has been inserted is to attempt mounts.

The MMC/SD socket also does not permit detection of the write-protect (or "lock") switch present on SD cards. "Locked" cards will therefore not be detected which means that despite the switch position, it is still possible to write to them since the lock switch does not physically enforce write protection.

## 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 are just three flags specific to this port:

-mcpu=arm9

  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=arm9 is the correct option for the ARM926EJ CPU in the AT91SAM9263.

-mthumb

  The arm-eabi-gcc compiler will compile C and C++ files into the Thumb instruction set when this option is used. The best way to build eCos in Thumb mode is to enable the configuration option CYGHWR_THUMB.

-mthumb-interwork

  This option allows programs to be created that mix ARM and Thumb instruction sets. Without this option, some memory can be saved. This option should be used if -mthumb is used. The best way to build eCos with Thumb interworking is to enable the configuration option CYGBLD_ARM_ENABLE_THUMB_INTERWORK.

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