This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/osmocom-sdr@lists.osmocom.org/.
Oliver Jowett oliver.jowett at gmail.com(Caveat: I don't have a FC0012 and I'm mostly guessing at the meaning of the GPIO registers here..) On 7 November 2017 at 18:38, David Kozub <zub at linux.fjfi.cvut.cz> wrote: > I added some traces and I see the values after plugging in the tuner, just > after the call rtlsdr_set_i2c_repeater(dev, 1) in rtlsdr_open, are: > > GPD = 0x06 > GPOE = 0x19 > GPO = 0x18 > > so in my understanding initially: > * GPIOs 1 and 2 are set to INPUT > * GPIOs 0, 3 and 4 are set to OUTPUT > * output GPIOs 3 and 4 are set to 1, GPIO 0 is set to 0 > I read those values as: GPD ("direction"): pins 1,2 inputs, others outputs GPO ("output"): outputs 3,4 high, others low GPOE ("output enable"): output drivers for pins 0,3,4 enabled i.e. pin 0: driven low pin 1, pin 2: inputs pin 3: driven high pin 4: driven high pin 5, pin 6, pin 7: high impedance > With the code before the GPIO fix (ba64a745) the call > rtlsdr_set_gpio_output(dev, 5) read GPD and set its value to GPO while > dropping the 5-th bit from the GPD value. So it assigs the value 6 to GPO. > This sets all output GPIOs to 0: GPIOs 3 and 4 are dropped to 0. Then it > sets GPOE to the previous value of GPOE plus the 5th bit, so it sets GPIO 5 > to output and its output value is 0 because of the previous write. So now we have: pin 0: driven low pin 1, pin 2: inputs pin 3: driven low pin 4: driven low pin 5: driven low pin 6, pin 7: high impedance I don't know where does the value 5 come from. Is it possible some other > dongles have the tuner at GPIO 5? Or is it really supposed to be GPIO 4 and > it worked with 5 by accident - by pulling GPIO 4 to 0 accidentally? > > A friend of mine looked at the PCB of the dongle I'm using and he found > out that GPIO 4 seems to be connected - via a transistor - to the TC0012. > GPIO 5 didn't seem to be connected - at least not in an obvious way - to > the tuner. I have to say this was just a quick look, so we could have > missed things. > > Also, as there's a transistor in between... could it be that GPIO 4 is not > really tuner reset, but tuner power? But this would be rather philosophical > point. Either way, from my tests, GPIO 4 has to be set to 0 for the tuner > to be reachable. > "Working by accident" seems fairly plausible given that you didn't have any luck regardless of what you did with GPIO 5. It seems like it has to be either GPIO 3 or 4, and if your PCB works with 4 then that's a strong argument. Oliver -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/osmocom-sdr/attachments/20171107/70e0eda4/attachment.htm>