Table 9. low-power mode operation, Cs8900a – Cirrus Logic CS8900A User Manual
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DS271F5
CS8900A
Crystal LAN™ Ethernet Controller
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8). To exit SW Suspend, the host must write to
the CS8900A’s assigned I/O space (the Write
is only used to wake the CS8900A, the Write
itself is ignored). Upon exit, the CS8900A per-
forms a complete reset, and then goes through
a normal initialization procedure.
Any hardware reset takes the chip out of any
sleep mode.
Table 9 summarizes the operation of the three
low-power modes.
CS8900A Configuration
CS8900A Operation
SLEEP
(Pin 77)
HWStandbyE
(SelfCTL, Bit A)
HWSleepE
(SelfCTL, Bit 9)
SWSuspend
(SelfCTL, Bit 8) Link Activity
Low
1
1
N/A
Not Present
HW Standby mode: 10BASE-T
receiver listens for link activity
Low
1
1
N/A
Present
HW Standby mode: LANLED low
Low
0
1
N/A
N/A
HW Suspend mode
Low to
High
N/A
1
0
N/A
CS8900A resets and goes through
initialization
High
N/A
N/A
0
N/A
Not in low-power mode
High
N/A
N/A
N/A
SW Suspend mode
Low
N/A
0
1
N/A
SW Suspend mode
Low
N/A
0
0
N/A
Not in low-power mode
Notes: 1. Both HW and HW Suspend take precedence over SW Suspend.
Table 9. Low-Power Mode Operation