SMC Networks SMC91C95

Internal VS External Attribute Memory Map

The Internal VS External EPROM attribute

memory decodes are shown below. This allows

the designer to not require an external EPROM

device if the single or multi-function PCMCIA card

needs less than 512 bytes of configuration

information. As can be seen in the map, if 512

bytes of CIS or less is required, the nFCS and

nFWE output pins of the

SMC91C95 need not be used (if serial EEPROM

is being used). Internal to the SMC91C95, the

memory addressing logic will allow byte or word on

odd byte address access (A0=1), the SMC91C95

will generate an arbitrary value of zero (0) since

the PCMCIA specification states that the high byte

of a word access in attribute memory is a don’t

care. This allows backward compatibility to 8 bit

hosts.

Table 7 - Attribute Memory Address Using Serial EEPROM

ATTRIBUTE

MEMORYADDRESS EXTERNAL EPROM

STORE INTERNAL SRAM

STORE (512 BYTES) CONFIGURATION

REGISTERS

0 - 3FEh X

400h-7FFEh X

8000h - 803Eh X