Table 2 - Bus Transactions in PCMCIA Mode

 

A0

nCE1

nCE2

D0-D7

D8-D15

 

 

 

 

 

 

8 BIT MODE

0

0

X

even byte

-

((IOis8=1) + (nEN16=1).(16BIT=0))

 

 

 

 

 

 

 

 

 

 

 

 

1

0

X

odd byte

-

 

 

 

 

 

 

 

X

1

X

NO CYCLE

 

 

 

 

 

 

16 BIT MODE

0

0

0

even byte

odd byte

 

 

 

 

 

 

otherwise

0

0

1

even byte

-

 

 

 

 

 

 

 

1

0

1

odd byte

 

 

 

 

 

 

 

 

X

1

0

-

odd byte

 

 

 

 

 

 

 

X

1

1

NO CYCLE

 

 

 

 

 

 

16BIT = CONFIGURATION REGISTER bit 7 IOis8 = ECSR register bit 5

nEN16 = pin nEN16

For the modem function, the transactions are similarxcept that the modem is assumed to be 8 bit wide unless (IOis8=0) and (nMIS16=0).

NOTE: The IOis8 value should be identical in MCSR and ECSR if both functions are enabled.

8 Bit mode = (IOis8=1)+(nMIS16=1)

22

Page 22
Image 22
SMC Networks SMC91C95 manual Bus Transactions in Pcmcia Mode NCE1 NCE2 D0-D7 D8-D15, Even byte IOis8=1 + nEN16=1.16BIT=0