R70/R71 on debug v3 board ?

Harald Welte laforge at openmoko.org
Wed Feb 13 12:00:02 CET 2008

On Wed, Feb 13, 2008 at 07:25:41AM -0300, Werner Almesberger wrote:
> ALLEN_CHANG at fic.com.tw wrote:
> >  R70 and R71 don't mount on debug v3 (whatever version).
> Okay, we need to fix that.
> >  These two resistors are used for 3.3V bias to 1.8V.
> >  I check M58WR016KB's datasheet and NOR FLASH can program and erase on
> > VPP= 1.3V~3.3V. Therefore, we don't need these resistors.
> What we don't need is the voltage divider (and particularly not with
> 1% accuracy ;-)
> However, we still need to pull nNOR_WP up, for GTA02. As a general
> precaution, I think something like 10k would be better than 0R.
> So we should drop R70 (i.e., do nothing there) and put something on
> R71. And we also have to make sure that this change is made on all
> v3 boards that ship for/with GTA02 devices.

Werner, I think the idea was to control the nNOR_WP via some GPIO bits
of the FTDI 2232 chip, i.e. have it under host software control.

This is why the resistors are just a resistive divider to get the 1.8V.

- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
Software for the world's first truly open Free Software mobile phone

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