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Harald Welte laforge at gnumonks.orgHi Kevin,
On Sun, Jun 19, 2011 at 03:39:42PM +0200, Kevin Redon wrote:
> > However, I think there's one pretty serious problem in the hardware
> > design: The bus switch has something like at least 5 (rather 16Ohms) of
> > internal 'on' resistance between the sim card and the phone. While this
> > _might_ still work for I/O, nRST and CLK lines, it definitely doesn't
> > fly for the supply voltage (VCC).
>
> how about using SN74CB3Q3244 or equivalent ?
> it has max 9 Omhs Ron.
Even 9 Ohms can be a lot. We're not switching some unidirectional bus
lines here, but everything including the Vcc power line.
I guess it would be good if you could continue to debug why it is not
working, even with my rework where Vcc supplied directly by the SAM7.
Let's discuss this tomorrow when you're visiting.
Regards,
Harald
--
- Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/
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