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bazjo / radiosonde_hardware

Hardware Documentation of various contemporary Radiosondes
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Connection of TXD and RXD of the u-blox #3

Closed ramapongithub closed 2 years ago

ramapongithub commented 5 years ago

Hi, there seems to be a small error in the schematic of the GPS-part. According to the scan the capacitors C317 and C318 are directly connected to pin 21 resp. pin 24 of the u-blox on one side and GND on the other side. rear2

But the schematic shows them in series with the resistors R306 resp. R307, between resistor and GND.

gps_sch

bazjo commented 5 years ago

Totally right, must have gone through. Will fix when I'm at the schematic next time. Shouldn't be a big deal when interfacing with the sonde though

ramapongithub commented 5 years ago

Hold your horses and take your time. There may be one or two other issues around there. I will dig a little deeper and report.

ramapongithub commented 5 years ago

Found what bothered me. Between this two points is continuity, rear2_2 wich means that +3V_GPS is connected to the point between R301 and R302. This provides power to the oscillator and VDD_3V. I measured 0 Ohm at R301 and R302 , so probably acting as fuses. Schematic should then look something like this: gps_sch1

Prutzz commented 3 years ago

The resistor coming from GPS IC - XTAL_I (GPS_UNKNOWN) goes all the way back to the transmitter to (RADIO_UNKNOWN1). Both the GPS and Tx share the same Xtal.