Instruction Manual

28 DS271F5
CS8900A
Crystal LAN™ Ethernet Controller
CIRRUS LOGIC PRODUCT DATASHEET
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