>>>>> "Jim" == Jim Paris <jim@xxxxxxxx> writes:
...
>> But how do you keep e.g. a FT20x from being handled as USART? I added
>> a quirk in my approach, looking for the string "FT23" in the device
>> product description . More explanations in the code...
Jim> That part was intentional -- I think _all_ the FT-X chips should be
Jim> handled as a USART. What else would they be treated as? They're
Jim> not capable of being an I2C or SPI master, and no I2C or SPI
Jim> details are ever exposed to the USB host -- they are only slave
Jim> interfaces, and allow some other device to read and write into
Jim> their FIFO using a protocol other than RS-232. The host side
Jim> interface looks the same regardless of which chip you're using.
Jim> They're essentially like the FT245BM in that regard.
For none of the FTDI chips the kernel handles the special modes for now. For
programming you send control messages not handled by the kernel and e.g. for
MPSSE mode some other control message to initiate a mode switch needs to be
send. Later on bytes sent to the (former) UART interface are handled
different.
You have to use libftd2xx, libftdi or pure libusb commands to access the
special functions. So I think the new chips are more like the FTx232(H)
chips. But while the FTx232(H) always expose a uart interface after reset, I
think the non-UART parts switch to their special mode direct after reset.
So I think exposing the non UART FT-X chips as UART is no good idea!
>> Signed-off-by: Jim Paris <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Jim> Not sure what happened with the name there.
Adding the signed-off line was the last thing I did before sending the mail
and going to bed. Argh!
Bye
--
Uwe Bonnes bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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