GAL16V8 driven by 74HC

They're both CMOS, and should be perfectly compatible in both directions.

Must be some other problem.

John

Lathe_Biosas wrote: Hi

It is desired to connect a 74HC chip to a GAL16V8, unfortunatelly, as much as I can conclude the signal of the 74HC is not compatible with GAL16V8 inputs. Attaching 1k Ohm pull up resistors to the GAL pins didn't help.

Should the 74HC be changed for a 74LS? Could anyone give me a hint on how to solve these inconsistency or the 74HCs are not compatible with GALs?

Best Regards

'HC and GALS cohabitate just fine. Are the GAL pins programmed as inputs or outputs? I use 'HC with 22V10s all the time with no problems and no pull-ups or pull-downs. What are you trying to do? GG

Lathe_Biosas wrote: Hi

It is desired to connect a 74HC chip to a GAL16V8, unfortunatelly, as much as I can conclude the signal of the 74HC is not compatible with GAL16V8 inputs. Attaching 1k Ohm pull up resistors to the GAL pins didn't help.

Should the 74HC be changed for a 74LS? Could anyone give me a hint on how to solve these inconsistency or the 74HCs are not compatible with GALs?

Best Regards

'HC and GALS cohabitate just fine. Are the GAL pins programmed as inputs or outputs? I use 'HC with 22V10s all the time with no problems and no pull-ups or pull-downs. What are you trying to do? GG

Damn, Pooh, You're getting so snotty you have graduated to a John-Fields-Snot-Level rating ;-)

Is this not S.E.D? Why didn't you ask why the OP felt there was an incompatibility.

My rule is snot responses should be limited to students so lazy they're looking for a work-free answer to their homework.

And, of course, responses to anti-American revisionist historians ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

My conclusion is that what you think are GAL16V8 inputs are actually configured as outputs.

If you're sure you configured them as inputs, also look at Vcc to the GAL. I've seen them do really funky things when they don't get good power (and they suck a lot, like > 100mA).

Tim.

[snip]

OK, I'll go for that. Have a good evening!

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

I felt there was an incompatibility because connecting a 74LS, the circuit works with out problems, these behavoir has happened already in two circuits.

Did you read the specs? Looks to me like the thresholds _are_ TTL compatible, but that doesn't mean it won't work with CMOS inputs.

Are you experiencing problems? If so, what is happening?

Maybe Pooh Bear is correct ?:-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Isn't that why he asked a question? *Everybody* who asks any question has a basic understanding problem.

Ooh, tell us! Tell us!

John

Obviously you don't know much !

Have you considered a career in management instead ? You might go far. The pay is better too.

Graham

"Lathe_Biosas" schreef in bericht news: snipped-for-privacy@g43g2000cwa.googlegroups.com...

Should be right.

Output voltage of a (Texas) 74HC chip: Vol=0.1 max, Voh=4.9 min

Input voltage of a (Lattice) 16V8: Vil=0.8V max, Vih=2.0V min The input current is in the uA range, neglectable for an 74HC.

So you sure have a problem, but not the one you think you have.

petrus bitbyter

That's one area worth having a go at for sure. At least they bothered asking !

Since 74HC swings rail to rail I fail to see why the OP reckoned it could be

*incompatible* in any way. It's as good as it gets for heavens sake !

It clearly shows that the OP has a basic understanding problem.

I've met too many jerks of that style to have any remaining time for them - today at least - Boki's always worth some time though. ;-)

You really don't want to know about the 'row' I just had today. It was surreal.

LOL !

Well what's the odd leg pull between friends ? Helps keep your mind agile. ;-)

Graham

"Lathe_Biosas" schreef in bericht news: snipped-for-privacy@f14g2000cwb.googlegroups.com...

Makes me curious. What 74HC resp. 74LS are you talking about? What frequencies? Do you have long traces/wires between the components?

petrus bitbyter

Or as Roger Miller said in a song, "If you've a mind to". For the bonus point, name the song. ;-)

--
?

Michael A. Terrell
Central Florida

"You Can't Rollerskate in a Buffalo Herd"

Bob

You got it! Roger didn't mind singing silly songs. ;-)

--
?

Michael A. Terrell
Central Florida