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Electronics => Electronics => Topic started by: hazzer123 on April 15, 2007, 08:13:23 AM

Title: Digital signal timing diagrams
Post by: hazzer123 on April 15, 2007, 08:13:23 AM

I am writing a program for a PIC to interface with a DS1620 using its 3 wire bus. (Datasheet = http://datasheets.maxim-ic.com/en/ds/DS1620.pdf (http://datasheets.maxim-ic.com/en/ds/DS1620.pdf))

I am having problems with the timing diagram (pages 9 and 10)

What do the horizontal lined segments between the bytes sent along the DQ line mean?  Does it mean that it doesn't matter what the value of the DQ line is, or does it mean that the DQ line goes high sometime during that interval?

Harry

Title: Re: Digital signal timing diagrams
Post by: JonHylands on April 15, 2007, 09:46:10 AM

The horizontal lines show where that pin stays high or low (depending on whether the line is at the top or bottom).

- Jon

Title: Re: Digital signal timing diagrams
Post by: hazzer123 on April 15, 2007, 11:26:07 AM

Woopsie :D

I meant diagonal lines sorry :)

There are diagonally shaded hexagons between the bits sent over the DQ liine.

Thank you

Title: Re: Digital signal timing diagrams
Post by: JonHylands on April 15, 2007, 02:46:10 PM

I suspect what they're saying is it doesn't matter, because they only sample the data line just after the clock line rises.

Personally, I would just leave the data line where it is for the whole bit-period...

- Jon

Title: Re: Digital signal timing diagrams
Post by: hazzer123 on April 15, 2007, 03:20:16 PM

Ok thanks,

thats what i suspected, it is just that i read a small tutorial on the net that said that areas shaded with diagonal lines from bottom left to top right mean that the signal must go high during that period.

Cheers  :D