I am trying to build a dual DDS generator that is controlled by an Arduino Nano, with LCD screen and rotary encoder input.
(LCD screen was tested and it shows useful output)
1)-----
The inputs are 4 encoder knobs that are wired to two shift-in registers CD4021B.
Shift-in registers have 3 pins that are:
Pin 3 - serial output pin Q8
Pin 9 - parallel/ serial control - latch pin
pin 10 - clock - shift register clock pin
So I connect:
pin 3 of CD4021B to a dedicated SS pin (user-defined) on my Arduino Nano
Pin 9 of CD4021B MISO Digital pin 12 on Arduino Nano
Pin 10 of CD4021B is clock SCK Digital Pin 13 on Arduino Nano
2)-----
I already have an generator that I bought of AliExpress that is an AD9833 -based DDS generator with a breakout board, output filter and a crystal.
I tested the circuit. Arduino can control this board. But I want two boards and rotary encoder control.
I want two of my generators to work in sych with one another. I read that there is some way to desolder one of the crystals and wire the 2nd board to 1st board's crystal.
So I have my left and right board with soldered corners of the crystal labeled 1,2,3,4. If I remove one of the crystals, how do I wire it to the other one? Should I use a clock-amplifier IC or any isolation components? What kind?
Do I desolder one clock and connect pin 4 of another clock to the place where pin 4 of the desoldered clock was?
Could I destroy a crystal by using a multimeter to check for continuity between 1,2,3,4?
There isn't really a datasheet on this specific crystal that I could find. Only a generic INTERQUIP datasheet. So I am not sure what the 'pinout' of this crystal is or what kind of crystal it is.
Engraving on it tells me that it is " INTERQUIP 25.000 MHz L11B "
3)-----
I have my DDS board hooked up to:
SS Digital Pin 10 on Arduino Nano..>>> FNC - on the AD9833 board
MOSI Digital Pin 11.......................>>> DAT - on the AD9833 board
SCK - Digital Pin 13.......................>>>CLK - on the AD9833 board
If I want to add a second board, do I connect:
MOSI Digital Pin 11.......................>>> DAT - on the AD9833 board
SCK - Digital Pin 13.......................>>>CLK - on the AD9833 board
I should choose a different SS pin?
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Are those statements correct:
SS is user-defined, one for every device that uses serial communication
SCK is common for everybody
MISO for inputs (rotary encoder knobs) MOSI for outputs (my two DDS boards)
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Thank you.
Resources I used:
Tutorial on In-Shift:
Arduino Nano pinout:
http://www.robot-italy.net/downloads/pighixxx/nano.pdf
http://www.aliexpress.com/store/product/Free-shipping-AD9833-DDS-Signal-Generator-Module-wave-Circuit-Diagram/319884_582730375.html - wrong crystal shown
AD9833 board that I have - i always used this circuit diagram:
http://img.alibaba.com/img/pb/761/765/514/514765761_088.jpg - yes the image is cut off
[http://g04.s.alicdn.com/kf/HTB1SDObFFXXXXXnapXXq6xXFXXXb/202818290/HTB1SDObFFXXXXXnapXXq6xXFXXXb.jpg](http://g04.s.alicdn.com/kf/HTB1SDObFFXXXXXnapXXq6xXFXXXb/202818290/HTB1SDObFFXXXXXnapXXq6xXFXXXb.jpg - found a better circuit diagram) - found a better circuit diagram
