CS8920A View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
'CS8920A' PDF : 144 Pages View PDF
CS8920A
NORMAL MODE
- ISA drivers on
- Looking for normal frames
- Ignoring wakeup frames
RESET = 1
or
ISA = off
ISA = on
and WakeupEn = 0, as read
from the EEPROM
RESET = 1
RESET STATE
CS8920A Inactive during reset
Read PPEROM
Normal frames are ignored
ISA = off
and
WakeupEn = 1
(from the
EEPROM)
ISA = on
or RESET = 1
(qualified)
ISA = off
(causing reset = 1)
ISA = on
and
WakeupEn = 1
(from EEPROM)
WakeupEn = 0
(from software
over the ISA bus)
WakeupEn = 1
(from software
over the ISA bus)
SUSPEND MODE
CS8920A ISA drivers are off
Ignoring normal frames
looking for wakeup
ISA = on
or
RESET = 1
(qualified)
Receive
Wakeup
frame
ISA = off
or
RESET = 0
ISA = off
and
WakeupEn = 0
(from EEPROM)
STANDBY MODE
CS8920A ISA drivers are on/active
Ignoring normal frames
looking for wakeup
ISA = on
or
RESET = 1
(qualified)
Receive
Wakeup
frame
ASSERT EWAKE
DROPPING NORM
PACKETS
Ignoring wakeup frame
CS8920A drivers off
RxMiss occuring
ASSERTING EWAKE
or GENERATE INTRQ
Deassert WakeupEn
RESET is defined as an ISA bus reset signal.
ISA off is defined as the sensing of the ISA signals in the power off state.
This is accomplished when MEMR_b = MEMW_b = IOR_b = 0, which can only happen when the ISA bus is power off.
Figure 5.14.Wakeup Frame State Diagram
116
DS238PP2
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