ON1BES Labo 2015                           DDS VFO  1-30MHz

Back to Index-page

No NL version - updated june 2017

Simple DDS Generator with Atmel 89C4051 and Nokia 3310 display

Attention : Be aware this is an old project build with a Atmel Flash chip and NOT an Atmel AVR chip.
But you can also use the newer Atmel 89S4051 AVR chip.

Based on an article by an New Zealand HAM ZL2PD and the necessary changes to my own project, this is a small and cheap DDS VFO generator.
As a self-contained generator, VFO, or in combination with a (homemade) transceiver, there are many application methods.
Think of a DRM radio, an SDR radio frequency generator, antenna analyzer and other stuff. . .
A unique feature is that a short time he can even be battery-fed with a 9 volt (100mA) bat.

Specifications :
- Digitally generated sine wave
- Adjustable from 1 Hz to 30 MHz min (with AD9850).
- Has a low-pass filter of 0 - 30MHz
- Minimum step is 10Hz, set in the software
- Has two VFO memory frequency's
- Used cheap recuperation Nokia GSM display (text and graphics)
- Is easy to assemble on two-part board
- Encoder may be a standard mechanical, or be made of an old PC mouse (Optical)
- Very nice finish possible with animation on display
- Is part of a transceiver or stand-along VFO generator
- Works on all HAM bands continuous or pre-set

Features on the Nokia display :
Line 1: max 14 characters of text including your own callsign.
Line 2: Displays VFO frequency channel A or B
Line 3: Placing the cursor with step indication in Hz, kHz or MHz
Line 4: Graphic analogue turn-direction indicator
Line 5: RIT frequency offset (in RIT Mode)
Line 6: Status line for VFO Lock, VFO A / B channel and Rx / Tx Mod

Functions of the buttons :
Step: Select VFO Frequency step in 10Hz, 100Hz or 1kHz step
Band: Select pre-set band 160m, 80m, 40m, 30m, 15m, 12m, 10m
RIT: Change tuning knob to RIT control allows a receiver to offset of 4 kHz in 10Hz steps
VFO A / B: Select one of the two VFO frequency's from memory
Lock: Lock the VFO frequency and the output DDS frequency
PTT: In RX or TX - Removed the IF and RIT offset of the VFO output frequency

Circuit :
DDS Schema
Photo's :


Inside 1
Inside 2
A1 A2

Board assembly
Board assembly MPU + Xtal board

Connections Nokia display :
The boards :                                                                

   The CPU - board :       The Key - board :
The 2 boards have been redesigned and equipped with plug connections to make a stack easily.
The power part was completely revised and updated with better placement and cooling on the keyboard print.
An additional stabilisator is provided to stabilyse the ERA-2 output.

Software :
The software is completely written in assembler, but can also be programmed with a Bascom 8051 programmer.
You can use the original software from ZL2PD and with a small change make your own call on the display.
Software Download for Bascom and printing (after click, look in your Folder "Downloads") : DDS 89C4052.ZIP

Files in the zip-file :
CPU-Print :  DDS_9850_ prt_cpu.pdf
Keyb.-Print : DDS_9850_prt_keyb.pdf
Cpu-layout : DDS_9850_cpu_lay.pdf
Keyb. Layout : DDS_9850_keyb_lay.pdf
Schematic : DDS_9850_sch.gif

mailmail: on1bes Scarlet.be