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306 AMD Geode™ SC3200 Processor Data Book
Core Logic Module - ISA Legacy Register Space
32581C
Table 6-47. Keyboard Controller Registers
Bit Description
I/O Port 060h External Keyboard Controller Data Register (R/W)
Keyboard Controller Data Register. All accesses to this port are passed to the ISA bus. If the fast keyboard gate A20 and reset fea-
tures are enabled through bit 7 of the ROM/AT Logic Control Register (F0 Index 52h[7]), the respective sequences of writes to this port
assert the A20M# signal or cause a warm CPU reset.
I/O Port 061h Port B Control Register (R/W) Reset Value: 00x01100b
7 PERR#/SERR# Status. (Read Only) Indicates if a PCI bus error (PERR#/SERR#) was asserted by a PCI device or by the
SC3200.
0: No.
1: Yes.
This bit can only be set if ERR_EN (bit 2) is set 0. This bit is set 0 after a write to ERR_EN with a 1 or after reset.
6 IOCHK# Status. (Read Only) Indicates if an I/O device is reporting an error to the SC3200.
0: No.
1: Yes.
This bit can only be set if IOCHK_EN (bit 3) is set 0. This bit is set 0 after a write to IOCHK_EN with a 1 or after reset.
5 PIT OUT2 State. (Read Only) This bit reflects the current status of the of the PIT Counter 2 (OUT2).
4 Toggle. (Read Only) This bit toggles on every falling edge of Counter 1 (OUT1).
3IOCHK# Enable.
0: Generates an NMI if IOCHK# is driven low by an I/O device to report an error. Note that NMI is under SMI control.
1: Ignores the IOCHK# input signal and does not generate NMI.
2 PERR/ SERR Enable. Generate an NMI if PERR#/SERR# is driven active to report an error.
0: Enable.
1: Disable.
1 PIT Counter2 (SPKR).
0: Forces Counter 2 output (OUT2) to zero.
1: Allows Counter 2 output (OUT2) to pass to the speaker.
0 PIT Counter2 Enable.
0: Sets GATE2 input low.
1: Sets GATE2 input high.
I/O Port 062h External Keyboard Controller Mailbox Register (R/W)
Keyboard Controller Mailbox Register.
I/O Port 064h External Keyboard Controller Command Register (R/W)
Keyboard Controller Command Register. All accesses to this port are passed to the ISA bus. If the fast keyboard gate A20 and reset
features are enabled through bit 7 of the ROM/AT Logic Control Register (F0 Index 52h[7]), the respective sequences of writes to this
port assert the A20M# signal or cause a warm CPU reset.
I/O Port 066h External Keyboard Controller Mailbox Register (R/W)
Keyboard Controller Mailbox Register.
I/O Port 092h Port A Control Register (R/W) Reset Value: 02h
7:2 Reserved. Must be set to 0.
1 A20M# Assertion. Assert A20# (internally).
0: Enable.
1: Disable.
This bit reflects A20# status and can be changed by keyboard command monitoring.
An SMI event is generated when this bit is changed, if enabled by F0 index 53h[0]. The SMI status is reported in F1BAR0+I/
O Offset 00h/02h[7].
0 Fast CPU Reset. WM_RST SMI is asserted to the BIOS.
0: Disable.
1: Enable.
This bit must be cleared before the generation of another reset.