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How to access the AD8555 register using PIC microcontroller?

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Inkwaterman

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ad 8555

Hi !

Someone has used the IC AD8555 from analog device, with a PIC microcontroller ? I need an example that explain how access in the IC register.

Thanx.
 

the tran

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Re: ad 8555

Please read the datasheet. Everything should be in there. If you still have problem, call AD and ask them for support.
 

Inkwaterman

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Re: ad 8555

the tran said:
Please read the datasheet. Everything should be in there. If you still have problem, call AD and ask them for support.

You are step ahead...

Thanks for yours illuminate councils !!!
 

gidimiz

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ad 8555

Hi,

I just read the PDF on the IC. It dosnt look that difficult.
BUT, you will have to use a scope. I dont see any other way to debug this.
They are saying that the word has to be 38 bits every time.
The 0 has to be 50 ns and 10 µs long, and the 1 has to be 50 µs or longer and The time between pulses should be at least 10 µs.
So, if you did all this and you have a scope then you will have to see the signal that is coming out from the pic.
The word must be in the format of Table 11. 38-Bit Serial Word Format.
 

Inkwaterman

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Re: ad 8555

gidimiz said:
Hi,

I just read the PDF on the IC. It dosnt look that difficult.
BUT, you will have to use a scope. I dont see any other way to debug this.
They are saying that the word has to be 38 bits every time.
The 0 has to be 50 ns and 10 µs long, and the 1 has to be 50 µs or longer and The time between pulses should be at least 10 µs.
So, if you did all this and you have a scope then you will have to see the signal that is coming out from the pic.
The word must be in the format of Table 11. 38-Bit Serial Word Format.

It's true , "It dosnt look that difficult" ....
I use a scope for debug and I'm sure that I send the 38 bit correctly.
But when I use the reading function, I see that the IC doesn't respond correctly. The response must start , if I have a good memory, after the 2 dummy bit . Instead the ad8555 put the DIGOUT pin high after the first bit send, and put down about at the middle of Start packet bit.

Moreover if I set a gain and I put a input signal, the output signal is not correct, therefore I have a problem also for the write operation.

any suggest ?

thanx
 

gidimiz

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Re: ad 8555

Hi,

Did you see this files and espacialy AN-730?
**broken link removed**

Also,
What Vdd are you usign for both parts? is it the same? if not, then you must insure that AD8555 has lower Vdd then your MCU.

. The response must start , if I have a good memory, after the 2 dummy bit . Instead the ad8555 put the DIGOUT pin high after the first bit send, and put down about at the middle of Start packet bit

Not true! ( if i read corectly )
on page 21 in the PDF they give few examples on how to set the AD8555, all data must start with 1000 0000 0001 and end with 0111 1111 1110. Also when you are reading, the code comes out the same.
Please check it again and let me know.
 

Inkwaterman

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Re: ad 8555

Not true! ( if i read corectly )
on page 21 in the PDF they give few examples on how to set the AD8555, all data must start with 1000 0000 0001 and end with 0111 1111 1110. Also when you are reading, the code comes out the same.
Please check it again and let me know.

My memory fails...
You have reason, after the end packet I can read the output of AD8555.

But my problem remain. I don't read a correct value..

Now I'll try to check the Vdd Value .

Thanks for now.

Added after 4 hours 9 minutes:

I think, It was a bad voltage regulator.
During the program phase the regulator doesn't give the correct amount of current and the action fails.

Thanx
 

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