User's Manual

LISA-U1/LISA-H1 series - System Integration Manual
3G.G2-HW-10002-2 Advance Information System description
Page 50 of 116
recognized, and the recognition of the subsequent characters is guaranteed only after the complete wake-up
(i.e. after 20 ms).
Figure 25 and Figure 26 show an example of common scenarios and timing constraints:
 HW flow control set in the DCE, and no HW flow control set in the DTE, needed to see the CTS line
changing on DCE
 Power saving configuration is active and the timeout from last data received to idle-mode start is set to 2000
frames (AT+UPSV=1,2000)
Figure 25 shows the case where DCE is in idle mode and a wake-up is forced. In this scenario the only character
sent by the DTE is the wake-up character; as a consequence, the DCE will return to idle-mode when the timeout
from last data received expires. (2000 frames without data reception).
CTS OFF
CTS ON
Active mode is held for 2000 GSM frames (~9.2 s)
time
Wake up time: up to 15.6 ms
time
TxD
module
input
Wake up character
Not recognized by DCE
Figure 25: Wake-up via data reception without further communication
Figure 26 shows the case where in addition to the wake-up character further (valid) characters are sent. The
wake up character wakes-up the DCE. The other characters must be sent after the “wake up time” of 20 ms. If
this condition is satisfied, the characters are recognized by the DCE. The DCE is allowed to re-enter idle-mode
after 2000 GSM frames from the latest data reception.
CTS OFF
CTS ON
Active mode is held for 2000 GSM frames (~9.2s)
after the last data received
time
Wake up time: up to 15.6 ms
time
TxD
module
input
Wake up character
Not recognized by DCE
Valid characters
Recognized by DCE
Figure 26: Wake-up via data reception with further communication