Re: swr_bridge.ino - Initial Success
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Steve, The "polarity" of the L402 , the transformers is important for it to work properly. It will either add or subtract from the phase of L400 depending upon which way the winding goes. We are also experiencing some differences between germanium and silicon detection diodes. The calibration needs a single variable bridge_compensation. The code is in read_power() function of sbitx.c.? This is in the later commits. - f
On Wed, May 3, 2023, 6:18 AM Steve Beckman < n3sb@...> wrote: Dave - I opted to run the digispark from 3.3 Volts. The 3.3V, Ground, SCL, and SDA signals were all grabbed from the exposed pins at the RTC Module. Current drain is <10 mA. I still may put a separate 3.3V regulator on the board to reduce power dissipation in the existing 3.3V regulators.
The digispark module seems to be happy running at 3.3 Volts at 16.5 MHz. The ATTiny85 spec sheet indicates this is probably pushing the speed ratings a bit, so I'll have to try selecting the 8 MHz clock option in the Arduino IDE.
Anyway - without the digispark module connected, I get the expected "i2cbb.c: writing address failed at 8" messages on the console during transmit. With the module connected, those errors are no longer printed to the console during transmit. So the sBitx software is now getting a response to its commands on the i2c bus at address 8.
I can also tickle the ADC inputs on the digispark module with my finger, and cause the Power and SWR readings to change on the GUI - which means the little module is working!
That's enough for one evening. I have the SWR Bridge built and ready to wire in, so the next step is to get the Bridge interfaced and calibrated. After that it will be time to experiment with code fixes.
Looks like this will be a viable way to add Power and SWR measurement functionality to the sBitx DE.
73; Steve, N3SB
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