Im trying to get the arduino to use this new AD9850 i have. I'm having difficulties trying to get a square wave output. http://www.ad7c.com/projects/ad9850-dds-vfo/ This link shows the board that i have. I have my pins wired respective to the following code.
/*
* A simple single freq AD9850 Arduino test script
* Original AD9851 DDS sketch by Andrew Smallbone at www.rocketnumbernine.com
* Modified for testing the inexpensive AD9850 ebay DDS modules
* Pictures and pinouts at nr8o.dhlpilotcentral.com
* 9850 datasheet at http://www.analog.com/static/imported-files/data_sheets/AD9850.pdf
* Use freely
*/
#define W_CLK 6 // Pin 6 - connect to AD9850 module word load clock pin (CLK)
#define FQ_UD 5 // Pin 5 - connect to freq update pin (FQ)
#define DATA 7 // Pin 7 - connect to serial data load pin (DATA)
#define RESET 4 // Pin 4 - connect to reset pin (RST).
#define pulseHigh(pin) {digitalWrite(pin, HIGH); digitalWrite(pin, LOW); }
// transfers a byte, a bit at a time, LSB first to the 9850 via serial DATA line
void tfr_byte(byte data)
{
for (int i=0; i<8; i++, data>>=1) {
digitalWrite(DATA, data & 0x01);
pulseHigh(W_CLK); //after each bit sent, CLK is pulsed high
}
}
// frequency calc from datasheet page 8 = <sys clock> * <frequency tuning word>/2^32
void sendFrequency(double frequency) {
int32_t freq = frequency * 4294967295/125000000; // note 125 MHz clock on 9850
for (int b=0; b<4; b++, freq>>=8) {
tfr_byte(freq & 0xFF);
}
tfr_byte(0x000); // Final control byte, all 0 for 9850 chip
pulseHigh(FQ_UD); // Done! Should see output
}
void setup() {
// configure arduino data pins for output
pinMode(FQ_UD, OUTPUT);
pinMode(W_CLK, OUTPUT);
pinMode(DATA, OUTPUT);
pinMode(RESET, OUTPUT);
pulseHigh(RESET);
pulseHigh(W_CLK);
pulseHigh(FQ_UD); // this pulse enables serial mode - Datasheet page 12 figure 10
}
void loop() {
sendFrequency(1); // freq
//while(1);
}
This should output 1 Hz according to the code however, when i connect an led to the output and ground i get nothing. The led doesn't even light up. My jumpers are set in the same way as in the image as in link described. Anybody see what i am doing wrong?
Are you sure the DDS square wave output pin is strong enough to drive a LED? Are you using a series resistor with the LED?
A scope would be a better way to validate the output pin of the DDS.
Does the LED on the DDS board light up?
Can you feed back the square wave output to the Arduino, and use the Arduino to measure frequency/light the Arduino's LED?
if i want 2 separate square waves 1 from each pin how would i go about doing that? (each at a different frequency)
If you read this:
SQW = Square wave outputs (complementary) Duty cycle adjustable with blue pot.
You wouldn't (or shouldn't ) be asking that. "Complimentary " is a simple concept revolving around the fact that if one output is the opposite logic state of the other output, the two outputs must therefore be the same frequency.
raschemmel:
Clearly you didn't read the datasheet.
Thank you for your reply, however there is no reason to be rude in your response. The data sheet is 20 pages long, it is very easy to miss details in a document with so much detail, more than half of which i have no understanding of. Negative attitude like this could discourage young people such as myself from taking further interest in such areas from a bad experience. I hope in the future if you do wish to reply you will do so without the negative commentary.
I am sorry you are offended. I don't see how making an observation that you failed to read the datasheet can be construed as being rude.
You are posting here because you want to learn . Our job here (whether you like it or not) is to point out your mistakes. If you had a professor he would say exactly the same thing to you that I did. Would you then say to him "you don't have to be rude " . I don't think so. You would say "Thank you sir ! May I have another sir ?" You are saying that because you are embarrassed by your mistake, as you should be. The schematic is not 20 pages long.
It is not even one page. It is a little corner of the page and it shows clock out and clock out (NOT) which , to anyone who can read a schematic, means complimentary outputs.
And if you want to use that excuse then let me respond with this:
Not reading the datasheet is not an option. I don't care how long it is. If you can't understand it and need to know something then ASK US ! How do find [this or that] in the datasheet ? Is there any reason you couldn't do that ? Do you think we are going to refuse ? The datasheet for the ATmega328 is over 500 pages long but if I need to know something I still look it up. I'm not going to crawl into bed with it like it's War and Peace but I'll still look something up.
You posted this :
Anybody see what i am doing wrong?
I was answering your question. If you don't want us to tell you what you are doing wrong then don't ask us to tell you what you are doing wrong. You asked for it. Next time , be careful what you ask for. If you want to learn, don't post on a forum whose very purpose is to tell you what you are doing wrong. Go post on a forum where they won't tell you because they don't want to hurt your feelings (which , it would seem , is more important than learning from mistakes) .
We're not here to stroke your ego. If you want to learn, check your ego at the door.
Get with the program. If you want to advance you knowledge in this line of endeavor, the proper response from you at this time is
"Thank you very much for taking time out of your busy day to point out my mistake. I appreciate your input and in the future I will try to pay more attention to detail when looking at a schematic, as a picture is worth a thousand words. I welcome your input on any future posts."
If you found my input helpful , feel free to click my karma button.....