When testing any digital device you may need to analyze the data communication channel, if any. At first sight this trivial task such as to take the timing charts from the necessary communication channel lines, determine the interface type and manually decode the taken timing charts, does not look like complex. But upon making some attempts to decode the timing chart you will not obviously want to perform this routine procedure that much. To set about decoding it is necessary at least to become familiar with specification of the analyzed interface and master its timing chart formats. It will take much time, especially when you have not any normal interface description within reach. Upon familiarizing with the interface you will know that the most interesting thing is decoding. Generally, in most of interfaces there are some signs of bytes transmission start and end, except for SPI, when the data are transmitted without any delay. That's why decoding starts with the signs searching. Upon finding, e.g. the start transmission sign, one start decoding the data and a lot of questions arise about particularities of the analyzed protocol that require examining the specification of the analyzed interface, comparing the timing charts with their analogs in specification. It can take your time; divert you from other and probably more interesting tasks. We can exemplify from experience about time expenditure for the interface timing charts decoding I2C (used in video capture board), when manually decoding for three and a half hours we managed to allot even 48 bytes, at that all obtained information was thoroughly recorded on a paper subject to any error. When decoding the same interface with analogous program (subsequent pilot model of logical analyzer) the whole communication cycle of 1026 bytes long was analyzed for 8 minutes but it took one and a half day to write the analysis program.

It does not mean that without any preliminary preparation one can decode the data of any interface by pressing a couple of buttons for several minutes. In any case before to analyze the selected interface it is strictly recommended to read its specification as no program can help you without comprehension of interface operation principles.

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