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2.4.2
Host Initiated Wake-up
In this example the UARTs are in a sleep mode and the Host initiates a wake-up.
Figure 3.
Host initiating wake-up to UARTs in sleep mode
Time Description
1
The UART interface is inactive, the Wireless CPU® and Host may be in a sleep (low
power) state at this point in time.
2
The Host initiates a wake-up request by asserting DTR1 & RTS1.
3
The Wireless CPU® acknowledges the wake-up request by asserting DSR1.
Generally, CTS1 would be asserted at the same instant. At this point both UART
interface are ready to accept data transfers, as indicated by the active states of their
respective hardware flow-control lines.
4
Data is sent by the Host.
5
Data is sent by the Wireless CPU®. Normal data flow can continue until such time as
the flow-control lines change their states, either to interrupt data flow temporarily
or to initiate another sleep request.
Sleep mode has to be enabled by the user before the sleep protocol
is affected. Each time power is re-cycled the Wireless CPU® will
default to sleep protocol OFF. In order to activate sleep protocol it
must be set to ON by using the AT Command AT*E2RS232 and
setting the appropriate <val>
NOTE
APPLICATION NOTE
GR/GS64 UART Sleep Protocols
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