FDC37M81 SMSC [SMSC Corporation], FDC37M81 Datasheet - Page 127

• Manufacturer Part Number: FDC37M81
• Description: PC98/99 Compliant Enhanced Super I/O Controller with Keyboard/Mouse Wake-Up
• Manufacturer: SMSC [SMSC Corporation]

When writing to the command and data port with hardware speedup, the IOW timing shown in the
figure titled “IOW Timing for Port 92” in the Timing Diagrams Section is used. This setup time is only
required to be met when using hardware speedup; the data must be valid a minimum of 0 nsec from
the leading edge of the write and held throughout the entire write cycle.
nIOW+n60=B
60=I/O Addr
64=I/O Addr
nAfterD1+B
nIOW+n64
nAfterD1
AfterD1
nCNTL
nIOW'
nAEN
nIOW
nDD1
GA20
AEN
DD1
CLK
D[1]
n64
n60
nA
0ns
Gate A20 Turn-On Sequence Timing
250ns
127
500ns