song

Hello to all menbers, can i use 74LS373 in place off 74HC373??
I didn't find one on my country.

0b00st0

No. The LS series uses TTL logic. The voltage levels of the logic level '0' is different and it could not reliable drive a CMOS input, which is what the ROM chip is.

song

Thanx man, i'm happy to see u again help me. (ma teacher)
You help me another day with my LS on chat room. Can u please add me on msn messenger?
haing_mz@ hotmail.com

Tom-Guy

I've used 74LS373, they do work. I believe I'd misplaced my sleeve of 74HC373's and stole it off of a junk OBD0 ECU laying around.

0b00st0

My bad, song. Looking through the datasheets, it seems as though most of the ROMS that we use are TTL compatible on the inputs and the outputs.

29C256 and SST27SF512 for sure and a few 27C256's I looked at as well.

You can always look at the datasheet of the ROM you are using and see if it has TTL compatible inputs.

2BG4HNDA

Wow if that was english im really stupid....im really stupid aren't i?...sigh....

Tom-Guy

I like you, Max. Don't take my argumentativeness for anything else than respect. You are really trying to apply technical knowledge... the problem is that real-world ---- is sometimes different than we think it is. I need to dig up that concept-boundary diagram, it explains it.

Just like Q31/IAT/purge, we empirically know that it happens, but the theory isn't all there. Maybe I'll sit down at my bench this fall after I've sold 90% of my car stuff, and figure out *why*, eh?

0b00st0

Thanx. Let me know how it goes. I think what happens is that the IAT sensor is rated to point that applying the purge output to it causes it to heat up slightly but to the point of no return. Increasing temp, decreasing resistance, increasing current, increasing temp, decreasing resistance................

I agree, real world is most of the time way different than what we expect, mostly because we never truly take into account all of the variables.

Tom-Guy

If you take a close look at a toasty IAT, you'll see how there isn't much to one. I seriously doubt it's a component rated at a 1/16th of a watt. The fact Q31 ***** 2/5ths the time is really scary in light of that... you'd think a power switching transistor would do a bit better dealing with heat/power.

song

Ok, i'm using Atmel At29c256, and i'll try to use the 74ls373 that i have and put the result here.
i hope that it worx becouse i don't have 74HC373 one.
Thanx u guys.