DS80CH11 Datasheet, PDF (55/88 Pages) Dallas Semiconductor – System Energy Manager

DS80CH11
9.0 HOST INTERFACE PORTS
9.1 OVERVIEW
The SEM provides three interface ports to the host CPU
which are hardware–compatible with the interface to the
8042 keyboard controller IC as it is used in conventional
PC system designs. One of the interface ports is
intended to be assigned to the standard keyboard con-
troller function. The host thereby communicates to the
SEM as a slave microcontroller in receiving key scan
inputs as it does with the 8042 in these systems. The
other two ports can be assigned as communication
channels to the SEM to support power management
and/or other functions.
MICROCONTROLLER SYSTEM INTERFACE PORTS Figure 9–1
A0
KBCS
PM1CS
REGISTER
ENABLE
DECODE
IOW
SD7–SD0
IOR
KBOBF
REGISTER
ENABLE
DECODE
PM2CS
SMI1
REGISTER
ENABLE
DECODE
SMI2
KBSTAT
STATUS REG.
KBDIN
INPUT
DATA BUFFER
KBDOUT
OUTPUT
DATA BUFFER
PMSTAT1
STATUS REG.
PMDIN1
INPUT
DATA BUFFER
PMDOUT1
OUTPUT
DATA BUFFER
PMSTAT2
STATUS REG.
PMDIN2
INPUT
DATA BUFFER
PMDOUT2
OUTPUT
DATA BUFFER
R/W
0ADH
RD
0AEH
INTERNAL
DATA BUS
R/W
0AFH
R/W
0BDH
RD
0BEH
R/W
0BFH
R/W
0F5h
RD
0F6h
R/W
0F7h
9.2 REGISTER MAPPING
The KBCS line is used by the host system in selecting
the keyboard system interface port, while the PM1CS
line selects the identical power management#1 inter-
face port and the PM2CS line selects the power man-
agement #2 interface port. Each set of system interface
registers occupy three memory locations in the SEM,
and the host. Table 9–1 summarizes access of the three
interface ports by the host system, and Table 9–2 sum-
marizes access to the port registers by the SEM.
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