Why is the application not running stand-alone?
Technical Note 21904
Arkitekturer:
ARM
Komponent:
debugger
Uppdaterad:
2015-10-16 13:05
Introduction
There can be numerous reason for an application not running. This Technical Note will focus on the following situation.
The situation is:
- The application only works when using the C-SPY debugger and with a connected debugger probe.
- The application does not work in stand-alone mode (that is, after disconnecting and power cycling the board).
Background
There are major differences between running an application using the C-SPY debugger, compared to running stand alone.
When debugging the application with the C-SPY debugger, a number of SFRs are set by:
- the flashloader source code.
- the mac file used by the flashloader.
- the mac file used by the application.
When the application runs standalone these SFRs need to be set by the application in the startup/initialization code.
There are also other possible explanations to why an application does not work in standalone mode. See solutions below.
Suggestions
- Check if a Flash loader is in use (Options > Debugger > Download). If a flash loader is configured, it probably means that a flash loader macro file is used. Check the
.board
and.flash
files for references to macro files.mac
. Open the macro file and see what it does. Consider if this needs to be done in the application startup code? Disabling the flash loader can be a way to find out. - Check if the application is using a Setup macro file (Options > Debugger > Setup). Open the macro file and see what it does. Is there a need to do the same in the application startup code? Disabling the setup macro file can be a way to find out.
- Using
printf()
in the application code can cause the application to hang forever when no debugger is connected, depending on the project settings. A way of checking the use ofprintf()
, is to set Options > General Options > Library Configuration > Library low-level interface set to 'None'.
For an ARM Cortex it is possible to keep the calls toprintf()
. If so, make sure that Options > General Options > Library Configuration > stdout/stderr is set to 'Via SWO'. - A non-disabled Options > General Options > Library Configuration > stdout/stderr > 'Via Semihosting' may cause the application to halt at a
BKPT
-instruction. TheseBKPT
are used by the semihosting system when sending the SWI interrupt for the semihosting. (Disable at Options > General Options > Library Configuration > Library low-level interface set to 'None'). - Certain hardware on the target device may need time to initialize (PLLs, etc). If the application does not wait for these kinds of intilizations, problems may occur. When running in a debugger, the application often halts at
main()
. This gives time to initialize, but when running the device stand alone, there will be no extra delays. To find out, add a long delay loop as the first thing in main(). If this helps, this points to the need to add code to wait for device initialization.
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