Emulator

[T Hergen]

27256
Vpp     1       28      Vcc
A12     2       27      A14
A7      3       26      A13
A6      4       25      A8
A5      5       24      A9
A4      6       23      A11
A3      7       22      OE~
A2      8       21      A10
A1      9       20      CE~
A0      10      19      O7
O0      11      18      O6
O1      12      17      O5
O2      13      16      O4
GND     14      15      O3



2732
A7      1       24      Vcc
A6      2       23      A8
A5      3       22      A9
A4      4       21      A11
A3      5       20      OE~/Vpp
A2      6       19      A10
A1      7       18      CE~
A0      8       17      O7
O0      9       16      O6
O1      10      15      O5
O2      11      14      O4
GND     12      13      O3

If you're trying to use a 27256 for a 2732,
pin 14 of what would have been the 27256 should
end up in pin 12 of the 2732 socket.

Pin 2 and pin 27 of what would have been the
27256 can't be left floating!  Tie them to ground.

Pin 1 of what would have been the 27256 may be
left unconnected.

Pin 28 of what would have been the 27256 should be
connected to pin 24 of the 2732 socket if you want to
power the device from unit you're plugging into.

The combined OE~/Vpp function of the 2732 only
functions as an OE~ as long as you're not applying
Vpp voltages to the pin (often 12v and up).

Check your pinouts and then check them again.

Use at your own risk.  I haven't tested this.



On Mon, 12 Oct 1998, Jason Weir wrote:

> I got a couple of questions that I thought you EE types out there might
> be able to help me with... First question the emulator uses power (80mA)
> from the target system, meaning that I have to boot the ECM with no data
> in the RAM... What I want to do is to add battery backup to the RAM that
> is on the emulator,  the RAM chip is a UT62256PC-70L   9615.. Anyone
> have any good advice on doing this mod?  Second question the cable is
> set up for a 27256 32K eprom and I want to use it with the 2732 4K
> eprom, What lines for the 32k do I leave out, and how do I set up for
> the 2732??  I have looked at both pinouts and the 27256 has separate
> lines for ~OE and VPP while the 2732 combines them?  Thanks for any help
> you can be...
> 
> --
> Jason Weir
> 88 Wrangler - 258 Chevy TBI
> Fayetteville, North Carolina
> http://home.att.net/~jweir/tbi/inject.htm  --- TBI Installation Page
> mailto:jweir at att.net
> 
>