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DDS v4.0 with Digibay/ebay module

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DDS v4.0 with Digibay/ebay module

Postby sprakashb » Sat Jun 01, 2013 5:18 pm

I have tried to use cheaper modules for AD9850 DDS from digibay.in with arduino and OM Niras's HamRadioIndia (HRI) design. It works fine with arduino. However when I connected the module to the HRI
it works but the output frequency is 1/3 of what is displayed. There is no offset and the on board oscillator freq is 125 MHz.

What could be the problem?

VU2SPF
SP Bhatnagar
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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Sun Jun 02, 2013 6:55 pm

Hi,
you should properly configure the System clock, using the calibration menu, see the doc with the hex file
73's
CNS
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Re: DDS v4.0 with Digibay/ebay module

Postby sprakashb » Mon Jun 03, 2013 9:09 pm

Dear OM Niras,
hanks for the reply.

I had to enter 41.5 MHz as clock frequency to get the near accurate frequency. The xtal osc on DDS module is of 125 MHZ. I had it programmed through arduino and it worked fine using 125 MHz clock. Why this difference?
73

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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Tue Jun 04, 2013 10:59 am

Kindly read the detailed document for the calibration menu and the system clock. This is designed for any clock frequency so you should set it first
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Re: DDS v4.0 with Digibay/ebay module

Postby sprakashb » Sun Jun 16, 2013 9:58 pm

Thanks OM Niras for your very kind help.I have put up some pictures of my DDS on vu2spf.blogspot.in :D
73
VU2SPF
Bhatnagar
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Re: DDS v4.0 with Digibay/ebay module

Postby YD3LUH » Thu Nov 28, 2013 10:02 am

sorry if this not a direct related question, can I ask for a new mode DDS controler ?
1.CW-up and CW-Down mode
2. Independent IF for every band select
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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Fri Dec 06, 2013 7:43 am

YD3LUH wrote:sorry if this not a direct related question, can I ask for a new mode DDS controler ?

This project was developed 7 years ago, so not interested to do any mods.
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Re: DDS v4.0 with Digibay/ebay module

Postby demetal » Sat Dec 28, 2013 8:12 pm

Hi,

I am using 9850 module from ebay and ddsv4.0 firmware, i set the multiplier as x1 and system clock as 125MHz, with all other offset to zero in calibration menu..but getting weird frequency only during the release of key or at the instance of stopping the encoder rotation, after few seconds the output returns to to null :roll: ... Also the frequency appearing during system clock calibration (10MHz as per document) is not constant and is varying always.. i checked the connections between dds and pic and its ok.. as per connected
# pin 6-->Fq_UD
# pin11-->W_clk
# pin13-->Data..
Could anyone let me know if encountered similar result..or solution for the same.. thank you.
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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Sun Dec 29, 2013 1:00 pm

Hi,
All DDS data ports (D0 to D7) should be connected as per the DDS 4.0 schematic.
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Re: DDS v4.0 with Digibay/ebay module

Postby demetal » Sun Dec 29, 2013 6:30 pm

Hi,

I cross checked the connections din found any bug... At last I found its generating frequency without fluctuation only when i "LOCK" the freq and sometimes only after multiple clicks on mode button (AFTER LOCKING the Freq) to make it change the modes... Do we need to "LOCK" the freq to get it in output port... ?? or is it just like set the freq and press # to get the output in the output port... ??

Thank you.
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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Sun Dec 29, 2013 7:48 pm

Please let me know, how you wired all 8 data inputs, i.e. D0 to D7
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Re: DDS v4.0 with Digibay/ebay module

Postby demetal » Sun Dec 29, 2013 8:05 pm

Hi,

I connected the pins as ...

# D0,D1 --> VCC
# D2,D3,D4,D5,D6 --> GND
# pin13-->D7 via 10K resistor
# pin 6-->Fq_UD via 10K resistor
# pin11-->W_clk via 10K resistor
# RESET --->GND
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Re: DDS v4.0 with Digibay/ebay module

Postby vu3cns » Sun Dec 29, 2013 9:04 pm

demetal wrote:# pin13-->D7 via 10K resistor
# pin 6-->Fq_UD via 10K resistor
# pin11-->W_clk via 10K resistor

PIN 25 D7
PIN 7 W_CLK
PIN 8 FQ_UD

As you see in the above posts, it works well with the ebay module. May be you can try with direct connection without 10K. Frequency lock is used to lock 'key pad' and 'encoder', not to lock dds output, it always stable.
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Re: DDS v4.0 with Digibay/ebay module

Postby demetal » Mon Dec 30, 2013 10:25 pm

hi,

got the bug... its the 10K resistor i placed in b/w the DDS and PIC as i followed the circuit schematic by PY2OOH ... seems weird :roll: ... will it create any potential issues if i power the dds with 3.3V and feed the control signals with 5V level from pic.. ? I tried with 5V supply to DDS but its getting warm after few seconds...

ThankYou.
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Re: DDS v4.0 with Digibay/ebay module

Postby BG4EJI » Sat Jan 11, 2014 6:33 pm

Will the "DDS VFO Ver 4.0" HEX file now? Where can I download?
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