Hello all,
I am writing a data acquisition program that writes data from the XMOS StartKit's ADC lines to a micro SD card. I seem to be running into this error when trying to write a buffer to the micro SD CARD.
It seems to be stopping after I fill the buffer and go to uplink the data in this function:
I use this data_write() function in another function called app() here:
If anyone could help, I would greatly appreciate it.
Tom
xrun: Program received signal ET_ILLEGAL_PC, Illegal program
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tomshannon
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xrun: Program received signal ET_ILLEGAL_PC, Illegal program
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infiniteimprobability
Verified - XCore Legend
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- Joined: Thu May 27, 2010 10:08 am
HI,
I'm afraid I have no experience of that codebase, but from the exception type, my guess is that you have an out of bounds array write or something... Anyhow, you need more visibility so time to debug.
The PC is indeed illegal - it's odd aligned which would only happen if you had code trampled over. It looks like data rather than valid address.
RAM starts at 0x10000 (we don't use 0x00000 specifically so we can catch null pointers as this address range will cause an exception) and code is at the bottom of this space. RAM and stack are at the top so 0x1FFFC and below.. 0x48c148c1 is very much not a valid address!
You need to get some more visibility of what has happened so either run xgdb from the command line or use the debugger (Debug As) in the GUI.
Also read this https://www.xmos.com/published/how-find ... using-xgdb
This may be useful too if you prefer the GUI over command line
https://www.xmos.com/download/private/U ... 8590A).pdf
Find out what the contents of the SPC (save program counter) are, which will hopefully track down the section of code (I'm guessing C as XC has array bounds checks as standard) which caused the issue..
If you are using xgdb command line, once you can also set hardware memory access breakpoints by typing watch <my address> eg. watch 0x1fefc. You can place these at the end of arrays and see when bounds are exceeded.
Good luck!
I'm afraid I have no experience of that codebase, but from the exception type, my guess is that you have an out of bounds array write or something... Anyhow, you need more visibility so time to debug.
The PC is indeed illegal - it's odd aligned which would only happen if you had code trampled over. It looks like data rather than valid address.
RAM starts at 0x10000 (we don't use 0x00000 specifically so we can catch null pointers as this address range will cause an exception) and code is at the bottom of this space. RAM and stack are at the top so 0x1FFFC and below.. 0x48c148c1 is very much not a valid address!
You need to get some more visibility of what has happened so either run xgdb from the command line or use the debugger (Debug As) in the GUI.
Also read this https://www.xmos.com/published/how-find ... using-xgdb
This may be useful too if you prefer the GUI over command line
https://www.xmos.com/download/private/U ... 8590A).pdf
Find out what the contents of the SPC (save program counter) are, which will hopefully track down the section of code (I'm guessing C as XC has array bounds checks as standard) which caused the issue..
If you are using xgdb command line, once you can also set hardware memory access breakpoints by typing watch <my address> eg. watch 0x1fefc. You can place these at the end of arrays and see when bounds are exceeded.
Good luck!