Caple C871i Manual de usuario descargar pdf (Pagina 263)

100

101

Apple II Computer Info

One problem is that the ROMs have three enable/select pins; the PROM has two.

Another problem is that one of the enables (pin 18) is Select= Hi. Both of the

PROM enables are Select= Lo.

Fortunately, the Apple II uses only two select lines; so, the main thing you

need to add to an adaptor is an inverter-- like a 74LS04 or any other inverting

gate.

Something like this should work ...

ROM socket (top view)

__ _____

|__| |--24--- to PROM socket pins 24 & 21, and 74LS04 pin 14

|--23--- to PROM socket pin 23

|--22--- to PROM socket pin 22

|--21--- (no connect)

|--20--- to PROM socket pin 20

|--19--- to PROM socket pin 19

|--18--- to 74LS04 pin 1 <74LS04 pin 2 goes to PROM socket pin 18>

|--17--- 17 and other pins go to corresponding pins on PROM socket

...

___________|

------------------ pin 12 goes to PROM socket pin 12 and 74LS04 pin 7

74LS04 (top view)

__ __

| |_| |

--1--| o |--14--

| |

--2--| |--

... ...

--7--| |--

|_______|

Probably, a II+ will have the Language Card plugged into Slot 0. With the LC

plugged in the $F8 ROM used is going to be the one on the LC; so, this is where

you

would swap in the adaptor with the PROM.

An alternative to an adaptor would be to mod the ROM socket connections on

the

LC:

o- a 74LS04 IC would be dead-bug mounted to the LC

Apple II Computer Technical Information : Apple II Family Hardware Info

ftp://ground.ecn.uiowa.edu/2/apple2/miscinfo/hardware : May 2001 : 263 of 572

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Caple C871i Manual de usuario Pagina 263

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Caple C871i Manual de usuario Pagina 263

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