Apple Macintosh Portable ROM Expansion

It appears that you are using AdBlocking software. The cost of running this website is covered by advertisements. If you like it please feel free to a small amount of money to secure the future of this website.

50 pin Mac Internal ROM Expansion Connector 50 pin Mac Internal ROM Expansion Connector

Due to the unique nature of the Macintosh Portable, developers now have the ability to add ROM to the Macintosh. To provide for compatible shared use of this ROM space with Apple and other developers.

Pin Signal Description
1 +5V Vcc
2-24 A1-A23 Unbuffered 68HC000 address signals A1-A23
25-26 GND Logic Ground
27 /DTACK /DTACK input to 68HC000
28 /AS 68HC000 address strobe signal
29 /ROM_CS Permanent ROM chip select signal. Selects in range $90 0000 through $9F FFFF
30 16MHz_Clock 16 MHz system Clock
31 /EXT_DTACK External /DTACK signal that disables main system /DTACK
32 /DELAY_CS This signal is generated by the addressing PAL and is used to put the ROM board into the idle mode by inserting multiple wait states
33-48 D0-15 68HC000 unbuffered data signals D0-15
49-50 +5V Vcc

References

Category:Memory Connectors

 

© 1998-2017 – Nicola Asuni - Tecnick.com - All rights reserved.
about - disclaimer - privacy