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Subject: Read from Jukebox
From: nsauzede (nsauzede_at_yahoo.com)
Date: 2002-01-12


Hi !

After a long night of effort, I could successfully read the 16 first bytes of my own mod from the running jukebox
to my PC using the Ear jack.

Ok, I couldn't do more tests (I suppose there can be errors by downloading huger zone -- my bit-transfer method isn't robust)

Here is the principle :
The mod begins by reconfiguring the PB10 from RXD1 to simple IO mode. It select it for output.
Then, the jukebox is ready to send some bits to the PC.
For that, I used the parallel port (the jukebox line is connected to the ACK pin)

Then, the most complicated : I had to find a way to transfer 8bit frames through this poor line, without rs232 buffer, nor any sync clock..
The method is : first, the PC wait for a line change; then it measures time for the line to change again.
This time is stored, and it correspond to the approx duration of a "0" transmission by the jukebox; for a "1", it will have two times the same duration.

The problem of this approach is the result is VERY long, and the speed is not constant (00 is faster than FF)
But for now, it was the only solution..

So if someone has a best idea..

After that I can try to d/l the original f/w
(anybody has clue where it is in memory space ??? ROM region ?? Flash region ??)

--
Gizz.



Page was last modified "Jan 10 2012" The Rockbox Crew
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