[Hackrf-dev] obtaining RSSI from max2837

[Michał Byrecki]

Howdy,

This RSSI pin is multiplexed with temperature sensing circuits. I
haven't look through the code yet, but woudn't be surprised, if both
values are read by the LPC controller. That would multiplex two analog
values on the LPC adc input (so therefore Louie may be getting somewhat
strange trace on the oscilloscope).

Brgds,
Mike SP5BYK


Dnia 2016-06-06, pon o godzinie 17:30 +0800, Benjamin Yap pisze:
> Hi Louie!
> 
> I'm studying HackRF's schematic as well. I'm not quite sure if you got
> the connections right. Pin32 (RSSI) of the MAX2837 seems to be
> connected directly to Pin2 (ADC0_1/ADC1_1) of the LPC4320 processor.
> According to the 2837 spec sheet, the RSSI is an analog signal ranging
> from 0.4 to 2.2V with a slope of 30mV per dB. The analog signal is
> likely digitised by the 4320 processor to give a digital value. I'm
> not quite sure if anything on the schematic suggests a connection with
> the CPLD/headers. Not sure if I missed out anything. Might be tricky
> to breakout that pin.
> 
> Ben

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