Configuration — Platform-specific Configuration Options
The Cyclone V SX platform HAL package is loaded automatically when
eCos is configured for the
cyclone5-sx 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.
The platform HAL package supports four separate startup types:
- 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 services from RedBoot, including diagnostic output.
- This startup type can be used for finished applications which will be programmed into Flash. 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.
- This startup type can be used for finished applications that are to be loaded into the on-chip SRAM. 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.
- This startup type can be used for finished applications that can be loaded into RAM via RedBoot. The load address is set to the same as for RAM applications, however, the application will be self-contained with no dependencies on services provided by other software. eCos startup code will perform all necessary hardware initialization. Once started, this application takes full control of the system and RedBoot will not be called again. This means that debugging via RedBoot will not be possible, only JTAG-based hardware debugging is supported. The intent of this startup type is to allow SMP test programs to be run from RedBoot, most SMP applications should use the ROM startup type. This startup type can also be used for applications loaded directly 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
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.
The Cyclone V SX board contains an 128Mbyte Micron N25Q00AA SPI serial
NOR flash device attached to the QSPI controller. The
CYGPKG_DEVS_FLASH_SPI_M25PXX package contains
all the code necessary to support this part and the platform HAL
package contains definitions that customize the driver to the
Cyclone V SX. This driver is not active until the generic
Flash support package,
included in the configuration.
This driver is capable of supporting the JFFS2
filesystem. However, note that the SPI interface means that this
file system has reduced bandwidth and increased latency compared
with other implementations. All that is required to enable the
support is to include the filesystem
CYGPKG_FS_JFFS2) and any of its package
CYGPKG_LINUX_COMPAT) together with the flash
The board uses the HPS's internal GMAC Ethernet device attached to
an external Micrel KSZ9021 Gigabit PHY. The
CYGPKG_DEVS_ETH_DWC_GMAC package contains all the
code necessary to support this device and the
CYGPKG_DEVS_ETH_CYCLONE5_SX package contains
definitions that customize the driver to the board. This
driver is not active until the generic Ethernet support package,
CYGPKG_IO_ETH_DRIVERS, is included in the
The Cyclone V SX board has a Maxim DS1339C I²C based RTC chip
installed. For the functionality used by eCos, this device is
compatible with the DS1307. Therefore, the
contains all the code necessary to support this device. This
driver is not active until the generic wallclock device support
CYGPKG_IO_WALLCLOCK, is included in
the configuration and I²C support is enabled.
The board uses the HPS's internal watchdog
contains all the code necessary to support this device. Within
that package the
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
UART Serial Driver
The board uses the HPS's internal UART serial support as described in the HPS processor HAL documentation. Only one serial connector is available on the board, which is connected to UART0 via a USB bridge. Only the UART data lines are connected to the bridge, so hardware flow control is not supported.
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. The following flags are specific to this port:
The arm-eabi-gcc compiler supports
many variants of the ARM architecture. A
-moption should be used to select the specific variant in use, and with current tools
-mcpu=cortex-a9is the correct option for the CPU in the HPS.
The arm-eabi-gcc compiler will
compile C and C++ files into the Thumb2 instruction set when
this option is used. The best way to build eCos in Thumb mode
is to enable the configuration option
- The Cortex-A CPU allows unaligned memory accesses and the default for arm-eabi-gcc is to generate instructions that make unaligned accesses. However, for this port, alignment exceptions are enabled, so unaligned accesses should not be made. This option disables unaligned accesses. Note that there is a performance and code size cost in doing this, since all accesses to unaligned data must now be made using individual byte accesses.
|2019-09-17||eCosPro Non-Commercial Public License|