forked from Michel2/pytimex
Clarification in timing documentation
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+9
-5
@@ -38,13 +38,16 @@ approximately 488 µs. So this sort of makes sense.
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Data transfer using CRT is done at 640x480@60Hz. At this resolution and
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frequency, the horizontal refresh frequency is 31.46875 kHz, so one line
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is drawn approximately every 31.78 µs. Using these timings, we can
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quantify the above measurements and conclude that one bit is one line and
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quantize the above measurements and conclude that one bit is one line and
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a bit is sent every 15 lines. The watch seems to be a bit flexible on
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this though.
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Data bytes are separated by approximately 2 ms, and packets are separated
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by approximately 240 ms. The interpacket delay is also present after
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each block of synchronization bytes.
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by approximately 240 ms. The interpacket delay is also present after each
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block of synchronization bytes (i.e. after all 0x55 is sent and after all
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0xAA are sent). The 2 ms interbyte delay happens to be the same time it
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takes to send two bytes at 9600 baud, in this case the computer sending
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the data byte and receiving confirmation it was sent.
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## Synchronization
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@@ -68,7 +71,8 @@ The character set is:
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0123456789
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abcdefghijklmnopqrstuvwxyz
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!"#$%&'()*+,-./:\[divide]=[bell symbol]?
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[Underscore][underscored check mark][left arrow][right arrow][big square][small square]
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[Underscore][underscored check mark][left arrow]
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[right arrow][big square][small square]
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```
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The small square can be used only on unpacked strings, since on packed
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@@ -303,7 +307,7 @@ and that space is used for a number instead.
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Another peculiarity is that you can send multiple numbers for the same
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name by completely omitting the name, not even sendig a string
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terminator, on successive messages. These packages will always be 7 bytes
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terminator, on successive messages. These packets will always be 7 bytes
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long.
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