Current Bootchart / breaking SD boot

Joe Pfeiffer joseph at
Thu Jul 10 02:29:31 CEST 2008

Werner Almesberger writes:
>Joe Pfeiffer wrote:
>> I'm confused -- do you mean there is no way to turn off the modem's RF
>> amp?  What do other phones using it do to comply with airplane
>> regulations?
>The RF amplifier has an input called TX_ENABLE, which is connected to
>TSPACT09 of the GSM baseband processor, so the GSM chipset can tell it
>whether to transmit or not.

So, in your previous post

>That AT at POFF doesn't cut power to the modem. Instead, it tells the
>modem to "power down", i.e., to enter its own standby mode, from
>which it can be awakened by "pressing" the modem's "on" button.
>(That "button" is in fact a transistor controlled by MODEM_ON line
>which connect to the CPU's GPB7.)

Are you drawing a distinction between 'turning the modem off'
vs. telling the transmitter not to transmit?  In the context of
airplane rules, the latter ought to be just as good...

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