Wednesday, December 24, 2014

Microcontrolller work

May daily jobs involves programming small processors. So I don't want to program at home.
However the transceiver requires a microcontroller so I did some programming anyway.

Stuff I use
-PIC 16F877 microcontroller running at 20 MHz.
-rotary encoder, LCD and several switches.
-2 x 74164 shift registers to select the band. No more IO pins were available.

Features so far:
-Tune the HF band an 160 Meter. The DDS is used as the LO.
-Basic RIT functionality
-Band selection By pushing a button and rotating the encoder. Band is outputted using the shift registers. They drive a relays using a transistor.
-Mode selection LSB,USB and CW by pushing a button an rotating the encoder. An mode dependent offset is added to the DDS frequency.

Features to implement.
-TX and RX handling like adding RIT offset while receiving. Maybe TX/RX in display.

In this state the controller and DDS should already be usable. I have not used it as a LO yet. I have to make an amplifier and a filter for the DDS output first. The frequencies out of the DDS seem OK.

Now I am working on the lowpass filters.



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