libftdi Archives

Subject: Re: EEPROM handling work

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Wed, 15 Sep 2010 19:03:55 +0200
>>>>> "DJ" == DJ Delorie <dj@xxxxxxxxxxx> writes:

    >> Daring now to give my code a try?

    DJ> When I get time, sure.  My tool can backup and restore eeproms
    DJ> anyway (based on my last attempt to do eeprom editing, which didn't
    DJ> go so well :)

    DJ> Hmmm... I'll try it on my ft2232h board, it has a blank external
    DJ> eeprom anyway.

    DJ> But the tool I ended up writing is a tweaker - it always reads the
    DJ> eeprom *anyway*, lets you tweak the values, then puts it back in:

    DJ>   $ ./eeprom -cbus2 io 1 device connected Dev 0: Filename "103",
    DJ> Manf "FTDI", Desc "FT232R USB UART", Ser# "A600dOgq" writing out new
    DJ> EEProm...

    DJ> I've not yet had the need to write out a whole new eeprom from
    DJ> scratch, so why is that the default use model?  I would think we'd
    DJ> want to encourage people to do a read/modify/write cycle instead,
    DJ> for chips with built-in eeproms like the 232R.

I hopefully will get back soon a batch of 26 boards with FT2232H and blank
93x66 on it.  So no easy way to tweak in that case.

But the other usage pattern the new code allows is:
* open device
* ftdi_read_eeprom()
* tweak values
* ftdi_erase_eeprom() (NOP) on FT232R
* ftdi_write-eeprom()

Even so my first mail was long, I shoudl have made it longer...


Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

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