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Core Logic Module
(Continued)
5.2.8
The Core Logic module can actively decode the keyboard
controller I/O Ports 060h, 062h, 064h and 066h, and gener-
ate an LPC bus cycle. Keyboard positive decoding can be
disabled if F0 Index 5Ah[1] is cleared (i.e., subtractive
decoding enabled).
Keyboard Support
Access to I/O Ports 060h and 064h on Sub-ISA can be
enabled with ROMCS# asserted, by setting bit F0 Index
53h[7]. The Core Logic module will also actively decode
the keyboard controller I/O Ports 062h and 066h if F0 Index
5Bh[7] is set.
5.2.8.1
Fast Keyboard Gate Address 20 and CPU
Reset
The Core Logic module monitors the keyboard I/O Ports
064h and 060h for the fast keyboard A20M# and CPU reset
control sequences. If a write to I/O Port 060h[1] = 1 after a
write takes place to I/O Port 064h with data of D1h, then
the Core Logic module asserts the A20M# signal. A20M#
remains asserted until cleared by any one of the following:
A write to bit 1 of I/O Port 092h.
A CPU reset of some kind.
A write to I/O Port 060h[1] = 0 following a write to I/O
Port 064h with data of D1h.
The fast keyboard A20M# and CPU reset can be disabled
through F0 Index 52h[7]. By default, bit 7 is set, and the
fast keyboard A20M# and CPU reset monitor logic is
active. If bit 7 is clear, the Core Logic module forwards the
commands to the keyboard controller.
By default, the Core Logic module forces the deassertion of
A20M# during a warm reset. This action may be disabled if
F0 Index 52h[4] is cleared.
Figure 5-10. SMI Generation for NMI
PERR#
IOCHK#
F0 Index 04h[6]
SERR#
F0 Index 04h[8]
F0 Index 40h[1]
I/O Port 061h[2]
I/O Port 061h[3]
I/O Port 070h[7]
Parity Errors
AND
System Errors
NMI
SMI
F0 Index 04h: PCI Command Register
Bit 6 = PE (PERR# Enable)
Bit 8 = SE (SERR# Enable)
F0 Index 40h: PCI Function Control Register 1
Bit 1 = PES (PERR# Signals SERR#)
I/O Port 061h: Port B
Bit 2 = ERR_EN (PERR#/SERR# Enable)
Bit 3 = IOCHK_EN (IOCHK Enable)
AND
AND
AND
AND
OR
AND
OR
(No External Connection)