Random Pauses on SBC

So it was time to cross compile the Automon project to my ARM board. It starts fine but after a while, it appears that the serial reading misses an important delimiter character ‘>’. This results in a loop to infinity searching for this character. This is obviously a very serious problem. This is my theory: Debian Etch is currently running off an SD card. At times, writes have to occur to the SD card but these writes hang the whole system. The terminal connection to it, don’t even respond at these times. So I’m guessing this happens and some how the > gets discarded or losed in the serial I/O buffer. I would have thought that the buffer would still accept characters at a hardware level but it appears not. The ELM327 sends the ‘>’ character but when a SD write occurs, this character gets refused and is dropped. Eventually my system will be running of NAND on-board flash and I don’t think this will be a problem at all, but a temporary solution will be to implement a timeout feature when searching for the > character. This may require another thread however. I’ll look into this later on.

Sunday, February 22nd, 2009 ELM327 Interface, Embedded Linux, Single Board Computer

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