LSI LSI53C895A, Technical Manual

Page: 108 / 364

3-20 Signal Descriptions
•
MAD[3:1] – These pins are used to set the size of the external
expansion ROM device attached. Encoding for these pins are listed
in
Table 3.15 (“0” indicates a pull-down resistor is attached, “1”
indicates a pull-up resistor is attached).
•
MAD[0] – This pin is the slow ROM pin. When pulled up, it enables
two extra cycles of data access time to allow use of slower memory
devices.
Note: All MAD pins have internal pull-down resistors.
Table 3.15 Decode of MAD Pins
MAD[3:1] Available Memory Space
000 16 Kbyte
001 32 Kbyte
010 64 Kbyte
011 128 Kbyte
100 256 Kbyte
101 512 Kbyte
110 1024 Kbyte
111 no external memory present