MEC1322 Datasheet, PDF (150/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
The hardware GATEA20 state machine returns to state S1 from state S2 when CMD = D1, as shown in the following
figures:.
FIGURE 11-3:
GATEA20 STATE MACHINE
RESET
CMD !=D1
or
DATA
[IBF=1]
S0
CMD = FF
[IBF=0]
CMD !=D1
or
CMD !=FF or
DATA
[IBF=1]
CMD !=D1
[IBF=1]
CMD = D1
S2
[IBF=0]
CMD = D1
[IBF=0]
CMD = D1
S1
[IBF=0]
Data
[IBF=0, Latch DIN
Notes: GateA20 Changes When in S1 going to S2
Clock = wrdinB
CMD = [C/D=1]
Data = [C/D=0]
DS00001719D-page 150
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