This chapter documents the configuration of eCos. The process is
the same for any of the supported targets: you may select a
hardware target (if you have a board available), any one of the
simulators, or a synthetic target (if your host platform has synthetic
target support).
There are various ways to download an executable image to a
target board, and these involve different ways of preparing the
executable image. In the eCos Hardware Abstraction Layer (HAL package)
there are configuration options to support the different download
methods. Table 11-1 summarizes the
ways in which an eCos image can be prepared for different types of
download. This is not an exhaustive list, some targets define
additional start-up types of their own. Where a ROM Monitor is
mentioned, this will usually be RedBoot, although on some older, or
low resource, targets you may need to use CygMon or the GDB stubs ROM,
see the target documentation for details.
Table 11-1. Configuration for various download methods
Download method
HAL configuration
Burn hardware ROM
ROM or ROMRAM start-up
Download to ROM emulator
ROM or ROMRAM start-up
Download to board with ROM Monitor
RAM start-up
Download to simulator without ROM Monitor
ROM start-up
Download to simulator with ROM Monitor
RAM start-up
Download to simulator ignoring devices
SIM configuration
Run synthetic target
RAM start-up
Caution
You cannot run an application configured for RAM start-up
on the simulator directly: it will fail during start-up. You can
only download it to the simulator if
you are already running RedBoot in the simulator,
as described in the toolchain documentation
or you load through the
SID
GDB debugging component. This is not the same as the simulated
stub, since it does not require a target program to be running to
get GDB to talk to it. It can be done before letting the simulator
run
or you use the ELF loader component to get a program into memory.
Note: Configuring eCos' HAL package for simulation should
rarely be needed for real development; binaries built with such
a kernel will not run on target boards at all,
and the MN10300 and
TX39 simulators can run binaries built for stdeval1 and jmr3904
target boards.
The main use for a ``simulation'' configuration
is if you are trying to work around problems with the device drivers
or with the simulator. Also note that when using a TX39 system configured
for simulator start-up you should then invoke the simulator with
the --board=jmr3904pal
option instead of
--board=jmr3904
Note: If your chosen architecture does not have simulator support,
then the combinations above that refer to the simulator do not apply.
Similarly, if your chosen platform does not have RedBoot
ROM support, the combinations listed above that use
RedBoot do not apply.
The debugging environment for most developers will be either
a hardware board or the simulator, in which case they will be able
to select a single HAL configuration.
