Author Topic: Digital Timing  (Read 4125 times)

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Offline Shenandoah

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Digital Timing
« on: July 26, 2013, 09:30:37 pm »
Hi all,

I'm now studying digital design...and one thing I cannot comprehend how timing works in digital circuits. For instance how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?  :-//

Thanks.
 

Offline dfmischler

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Re: Digital Timing
« Reply #1 on: July 26, 2013, 10:36:10 pm »
Hi all,
... how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?

There are several different ways to do that.  Most simple systems are synchronous.  Do you have a particular family of parts in mind?  If so, we can probably come up with the appropriate details.  Otherwise, check out this for Z80 (TIMING starts on page 11).  There are both simpler and more complex ways to get this done.
« Last Edit: July 26, 2013, 10:38:18 pm by dfmischler »
 

Offline madires

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Re: Digital Timing
« Reply #2 on: July 26, 2013, 10:37:38 pm »
I'm now studying digital design...and one thing I cannot comprehend how timing works in digital circuits. For instance how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?  :-//

Most logic/digital ICs got control pins to deal with that problem. For example the IC putting data on the bus might have a "output enable" trigger pin and the receiver a "take input" pin. To time both ICs correctly you could use a MCU controling both ICs or you would put some logic in between to trigger the outputting IC and delay the "take input" signal (with an even number of inverters or whatever you got) to give the outputting IC enough time. Or you use a system clock and some logic to drive all ICs in a specific sequence timed by the clock. The important thing to know is that all ICs need some time to do their job and the datasheet gives you the timing details. For more complex systems the bus will have several control/handshake lines to control communication. LCD modules are a good example.
 

Offline free_electron

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Re: Digital Timing
« Reply #3 on: July 26, 2013, 10:55:56 pm »
Hi all,

I'm now studying digital design...and one thing I cannot comprehend how timing works in digital circuits. For instance how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?  :-//

Thanks.

You need to build a waferfab first and design chips. Then it will all become clear...
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline M. András

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Re: Digital Timing
« Reply #4 on: July 27, 2013, 10:04:31 am »
Hi all,

I'm now studying digital design...and one thing I cannot comprehend how timing works in digital circuits. For instance how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?  :-//

Thanks.

You need to build a waferfab first and design chips. Then it will all become clear...

simple sentences reveal the true knowledge of the self promoted young genius right? :D:D:D
 

Offline madires

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Re: Digital Timing
« Reply #5 on: July 27, 2013, 01:15:32 pm »
You need to build a waferfab first and design chips. Then it will all become clear...

simple sentences reveal the true knowledge of the self promoted young genius right? :D:D:D

I don't know if he meant it in a figurative sense, but there is one ;-) All the prodution processes in the waferfab need to be timed and run in a specific sequence.
 

Offline M. András

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Re: Digital Timing
« Reply #6 on: July 27, 2013, 01:35:30 pm »
You need to build a waferfab first and design chips. Then it will all become clear...

simple sentences reveal the true knowledge of the self promoted young genius right? :D:D:D

I don't know if he meant it in a figurative sense, but there is one ;-) All the prodution processes in the waferfab need to be timed and run in a specific sequence.
yes its meant to be figurative. seriously the guy wanted to open a waferfab and he ask these sort of questions.
 

Offline 4to20Milliamps

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Re: Digital Timing
« Reply #7 on: July 27, 2013, 02:36:50 pm »
It sounds like you just need a better tool to visualize the process flow, this may not be the answer you are looking for but I would sit down and get a good idea of what you want your circuit to do then do a step by step analysis of how to go about doing it.

http://www.technologystudent.com/despro_flsh/progm1.html

I'm sure there are free tools out there but I found this as an example:

http://www.assemblyflowchart.com/

 

Offline Shenandoah

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Re: Digital Timing
« Reply #8 on: July 28, 2013, 04:43:53 pm »
Hi all,

I'm now studying digital design...and one thing I cannot comprehend how timing works in digital circuits. For instance how can I tell a specific part of the system that's it's okay to put its output on a bus so that the other part can process it, and then tell the another part that it's ready to read that output?  :-//

Thanks.

You need to build a waferfab first and design chips. Then it will all become clear...

You loser...why r u afraid of other people knowledge??? A typical loser, probably old fart loser.
 

Offline M. András

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Re: Digital Timing
« Reply #9 on: July 28, 2013, 05:08:30 pm »
yeah but the man you call a loser works at a semiconductor company and published enough work to earn a credit and represent his knowledge, while you are posting dreams without foothold
 

Offline free_electron

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Re: Digital Timing
« Reply #10 on: July 28, 2013, 06:07:13 pm »
You loser...why r u afraid of other people knowledge??? A typical loser, probably old fart loser.
i think you suffer from bipolar disorder ... maybe they didn't bake you long enough in the oven after implant...

(That's a semiconductor process engineer joke, you may not understand)
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Offline SeanB

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Re: Digital Timing
« Reply #11 on: July 28, 2013, 06:30:30 pm »
More like they forgot the mask layer on his ASIC............... Just a sea of uncommitted gates now and no way to fix it.
 

Offline c4757p

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Re: Digital Timing
« Reply #12 on: July 28, 2013, 06:33:24 pm »
"Sea of uncommitted gates" and "missing the mask layer on your ASIC" are my new favorite insults.
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline SeanB

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Re: Digital Timing
« Reply #13 on: July 28, 2013, 09:05:11 pm »
You are welcome, sometimes I amaze even myself.
 

Offline free_electron

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Re: Digital Timing
« Reply #14 on: July 28, 2013, 09:41:56 pm »
he's missing a few masks in his stack ...
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