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| WIP: Reverse engineering the programming protocol for SiTime SiT8008 |
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| lty1993:
Hello, I got a SiTime Time Machine 2 and few blank SiT8008BI chips few days ago. Since I cannot find any information about programming protocol online, I would like to reverse it myself. It is been busy recently, the progress maybe slow. ============================================================================== [Dec 8, 2018] I managed to capture the programming waveform using a scope. (The model number I am programming to the blank device is SiT8008BI-21-XXN-8.000000) The channel 1 is OE/ST/NC, channel 2 is OUT, channel 3 is VDD. Here is hdf5 file I captured: CH1.h5 CH2.h5 CH3.h5 ============================================================================== |
| Rerouter:
It really looks like you have a serious amount of crosstalk. at a glance it looks almost like CH3 is used as a chip select, CH2 / CH1 as data pair, possibly SPI, Any chance you can clean up your crosstalk issue, and zoom in a bit on the waveform to get an idea of how the 3 pairs are transistioning, My best guess is the OE is used as MOSI, and the OUT as MISO, |
| lty1993:
It is really hard to probe the signal right without making a custom jig. Anyway, I do not think the cross talk will affect much on interpreting the signal. The OE is a three level signal as shown in next screenshot. I posted the hdf5 files for each channel in the original post. You can use matlab, infiniium offline, or something similar to analyze them. |
| Rerouter:
The image is a much easier thing to analyse than 1GB of files that I cannot open without specialized software, So far, CH1, is a clock, don't know what the positive bits are, but clearly 800,000 Hz To me its exactly like SPI, maybe a 1 wire variation on it, looks like update on falling clock, and read on rising. |
| amyk:
I suspect that it's not just a frequency that's directly programmed into the device, but dividers, drive strengths, and other parameters that the programmer tunes in order to get the right frequency output. |
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