IC for the 1989 OBD1 computer
08-30-2014, 03:14 PM
#1
Pro
Thread Starter
IC for the 1989 OBD1 computer
I was wondering if the 27C512-12 would be a working replacement for the stock IC? The 27C256 is the stock IC...I think. I came across a few of the 27C512-12 chips at my store. Just wondering if I can use them.
Thanks, Went
Thanks, Went
08-30-2014, 05:40 PM
#2
Melting Slicks
I'm not sure what the -12 designates. Who is the manufacturer of the chips in question? Anyway, I think they will work, they are just twice as big and you will have to set the program in the correct location. I think some people just double the .bin.
08-30-2014, 08:27 PM
#3
Pro
Thread Starter
The IC's are Texas. They just showed up and I thought they should work. I'll take them home.
Went
Went
08-31-2014, 01:26 AM
#4
Race Director
The main difference between the 27C512 and the 27C128 is the extra pin (A15) for the extended addressing:
Pin 1 is tied high in the ECM, so you would have to locate the program in the upper half of the chip.
The -12 is the speed to read a memory location in the chip: 120 ns = nanoseconds.
Pin 1 is tied high in the ECM, so you would have to locate the program in the upper half of the chip.
The -12 is the speed to read a memory location in the chip: 120 ns = nanoseconds.
Last edited by Cliff Harris; 08-31-2014 at 01:29 AM.