Dr. Werner Fink wrote: > > some questions for the real experts.
Not me then, when it comes to frontends. Anyway... > Accordingly to > > http://www-us2.semiconductors.philips.com/acrobat/datasheets/TSA5522_2.pdf > > the function tsa5522_set_tv_freq() in frontends/grundig_29504-491.c, > does not use the Charge-Pump bit CP in the third byte: > > u8 buf [4] = { (div >> 8) & 0x7f, div & 0xff, 0x8e, 0x00 }; > ^^^^ > > with the CP bit high the value would be 0xce. Is this intentional, > that means this make no sence on the DVB-S 1.6 tuner layout? > Or, which would be more a problem, would it be dangerous for the > DVB-S 1.6 hardware to set this bit high? AFAIK the charge pump setting has nothing to do with the tuner layout. A high setting means that the voltage at the varactor can change faster, but due to overshoot it may actually take longer to reach a stable frequency. OTOH I think it is usually a good idea to set the CP setting low *after* tuning for better stablity. If the data sheet does not document the best CP setting one can only experiment. You cannot damage your hardware by doing so. > Also the last byte may have some values for the last three bits > enabled because table 6 of the pdf at page 7 does not know all > bits low. > > Maybe a value 0x04 for 0.4Vcc1 (band B????) or something else > has to be set. I've no idea how the tsa5522 pins are connected in the Grunding frontend. It is well possible that they are unused. Johannes
