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DDS-VFO reconstructed #arduino #bitx40help #radiuno #firmware

 

Hi, I'm trying to reconstruct the raduino (DDS-VFO) for a BITX40. I used an arduino nano, a 16x2 display, a 10K multiturn potentiometer and a Si5351a card. All provisionally mounted on a breadboard. The scketch used is the raduino_v1.27.7 version
I copied the schematic connections and the arduino and the display work. Except that the frequency range is around 7.060 to 7.160 instead of 7,000 to 7,300 and I haven't tried it yet if something comes out of the Si5351!
Has anyone already tried to do it again ???
Tips???
Thanks and sorry for my English.
 

The OEM sketch for the BitX40 has a provision where it starts jumping up or down to the next tuning segment when you reach one end or the other of the tuning pot. In between the tuning is limited to a smaller range of the full band. Some have modified the pot circuitry to add push buttons to simulate end of rotation resistance values and step up or down.

=Vic=
James Lynes
 

With the multiturn pot you need to changed the pot span to 300 to cover the whole band without jump tuning.

Also,? set the starting frequency to where ever you wish to start on power on.

James
 

Si5351 I2C interface to Arduino should be 3.2 volt pull-up with 4.7K resistors.? This can be obtained from 3.2 regulated volts in the arduino.? Puulling I2C up to 5 volts may damage the Si5351 ( I found out the hard way!) .? Power your Si5351 from 3.2 volts as well.??

Demo code from QRP-Labs web site will work as a starting place but you will have to write your own tuning routine for your style of encoder or push-button tuning.??

Build two units and use the second as a signal generator for the workbench.??

Arv? K7HKL
_-_


On Sat, Jun 29, 2019, 11:51 PM SaMa photo SaMa photo <infosamaphoto@...> wrote:
Hi, I'm trying to reconstruct the raduino (DDS-VFO) for a BITX40. I used an arduino nano, a 16x2 display, a 10K multiturn potentiometer and a Si5351a card. All provisionally mounted on a breadboard. The scketch used is the raduino_v1.27.7 version
I copied the schematic connections and the arduino and the display work. Except that the frequency range is around 7.060 to 7.160 instead of 7,000 to 7,300 and I haven't tried it yet if something comes out of the Si5351!
Has anyone already tried to do it again ???
Tips???
Thanks and sorry for my English.
 

Thanks for the answers, but none of this!
Even if a 10K linear potentiometer does not change, the frequency range is from 7.060 to 7.160
While if I use the same sketch on the original raduino the frequency excursion makes it complete!
I do not understand....
 

I attach a video of my creation
and photos of the main components used

VID_20190701_093654.mp4
VID_20190701_093654.mp4

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