Re:Why Writing Firmware Is Kinda Like Software Exploitation
by cnvogel on Saturday March 22, 2014 @05:10AM
(#7448378)
Edit: Shame on me, should have read the article more carefully, he actually explains why he was not able to use JTAG. Sorry for my hubris.
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I like the approach, but while this post rants about the unprofessional Arduino crowd, his attempt to solve his init problem via a blinking LED to Morse debug data strikes me as similarly inefficient.
To solve these kinds of problems, one normally attaches a JTAG interface (or the equivalent device on the particular platform) and single steps through the code, observing registers and memory... if you don't have this tool (for ARM the most primitive will cost you maybe 30$ or €, the fastest and most feature rich will be s few 1000) you'll waste a LOT of time in low level debugging.
If you really have to Morse on a GPIO, you want something that a logic analyzer can decode.
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I like the approach, but while this post rants about the unprofessional Arduino crowd, his attempt to solve his init problem via a blinking LED to Morse debug data strikes me as similarly inefficient.
To solve these kinds of problems, one normally attaches a JTAG interface (or the equivalent device on the particular platform) and single steps through the code, observing registers and memory... if you don't have this tool (for ARM the most primitive will cost you maybe 30$ or €, the fastest and most feature rich will be s few 1000) you'll waste a LOT of time in low level debugging.
If you really have to Morse on a GPIO, you want something that a logic analyzer can decode.