libftdi Archives

Subject: Re: Any exported way to set read timeout or query receive buffer?

From: Paul E Ourada <paul@xxxxxxxxxxxxxxxxxxx>
To: Rogier Wolff <R.E.Wolff@xxxxxxxxxxxx>, "libftdi@xxxxxxxxxxxxxxxxxxxxxxx" <libftdi@xxxxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 19 Feb 2019 21:05:20 +0000



From: Rogier Wolff <R.E.Wolff@xxxxxxxxxxxx>
Sent: Friday, January 18, 2019 8:11 AM
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Subject: Re: Any exported way to set read timeout or query receive buffer?
 
On Fri, Jan 18, 2019 at 04:05:29PM +0100, Thomas Jarosch wrote:
> Hi Uwe,
>
> You wrote on Mon, Dec 17, 2018 at 04:56:09PM +0100:
> > For a user programm to determine if a connected FTDI device has the 60
> > MHz clock option (e.g. FT2232H) or not (e.g. FT2232D), I only see on
> > way:
> > - Send the  Disable Clk Divide by 5 command (0x8a)
> > - Observe if the command is accepted or not.
>
> any chance to detect the device by USB PID
> or serial number, product description?

When a new device is introduced that is mostly compatible with an
earlier version, there is pressure to use the old PID/VID. This will
cause existing drivers and applications to automatically pick up the
new device. On the other hand, chosing a new PID will mean that
existing drivers have to be patched to now also accept the new PID.

But after a while, having a new PID becomes nice. The software can
use/workaround quirks caused by the different devices.


I would think it quite possible that FTDI occasionally makes the wrong
decision (use old PID) instead of the right one (always issue a new
PID).

Was this for a generic or a custom device? If it's custom, then I suggest implementing a configuration flash eeprom which can take custom manufacturer and product ID strings. Then it's obvious which device you are working with.

Paul

        Roger.

--
** R.E.Wolff@xxxxxxxxxxxx ** http://www.BitWizard.nl/ ** +31-15-2049110 **
**    Delftechpark 11 2628 XJ  Delft, The Netherlands. KVK: 27239233    **
*-- BitWizard writes Linux device drivers for any device you may have! --*
The plan was simple, like my brother-in-law Phil. But unlike
Phil, this plan just might work.

--
To unsubscribe send a mail to libftdi+unsubscribe@xxxxxxxxxxxxxxxxxxxxxxx  



libftdi - see http://www.intra2net.com/en/developer/libftdi for details.
To unsubscribe send a mail to libftdi+unsubscribe@xxxxxxxxxxxxxxxxxxxxxxx


Current Thread