[Ftdi-usb-sio-devel] Baudrate setting is broken.

[Teunis v. B. <te...@gm...>]

Dear driver maintainers,

There is a serious bug regarding setting the baudrate.

Certain standard baudrates produce wrong baudrates during transmit:

baudrate set   baudrate produced

1200  ->  9600
2400  ->  +/-35700

4800  ->  4800
9600  ->  9600
19200  ->  19200
38400  ->  38400

57600  ->  +/-500000
115200  ->  +/-570000

As you can see, baudrates lower than 4800 or higher than 38400 are set wrong.

I measured this using an oscilloscope. Other parameters I used: 8
databits, no parity, 1 stopbit.

I did check this with two different converters from FTDI and Prolific:

idVendor=0403, idProduct=6001

idVendor=067b, idProduct=2303

I checked it with a desktop pc running openSuse 12.3 64-bit with
kernel 3.7.10 and
a laptop running Ubuntu 14.04 32-bit with kernel 3.13.0

Both converters work correctly on windows 7.

For the tests I used this code: http://www.teuniz.net/RS-232/

Let me know if you need more info/tests/measurements.

I hope you can fix this.

Best Regards,

Teunis van Beelen


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