Legacy-Free Keyboard/Embedded Controller with SPI and LPC Docking Interface
System is fully powered & the
8051is running keyboard code:
nRESET_OUT = 1, STP_CLK = 0
The host issues a defined
command to put the 8051 into
Idle mode
8051goes into idle mode
The host sets STP_CLK = 1
and combined with
nRESET_OUT=1 causes the
8051 clock to stop
The host can operate as
needed.
When done, the host resets
STP_CLK = 0
NOTE: in order to leave idle m ode the 8051 m ust receive an interrupt
typically a software tim er interrupt will be used
N
Y
8051 IRQ?
(note)
8051 wakes from idle mode
and starts from where it left off
Figure 17.2 LPC Host Sequence to Stop the 8051
Revision 1.1 (01-14-03)
196
SMSC LPC47N350
DATASHEET
SMSC [ SMSC CORPORATION ]
