On Wed, 3 Jul 2013 at 23:35, Frank Schäfer wrote:
When I wrote the patch in 2009, only the first baud rate programming
method was in place.
The second method has been added later with commit 8d48fdf6.
Hmm - it would be interesting to know what device and tests that
change was based on.
Hmm... the comment says that
12MHz*32 / baud = divisor = (2^buf[1]) * buf[0]
But the code below does something different...
According to my tests the comment is true for bits 1..3 of buf[1] and
the current code seems to work by chance, because it doesn't get used
for baud rates below 115200.
I hope I'll get a FTDI-device for testing tomorrow.
I'll try to hook mine up to a logic analyzer tomorrow, so that I get
better timing results than from the "estimate the baud rate from the
time it takes to send and receive a few thousand bytes" method I used
so far.
cu
Reinhard
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