Siemens AC75 Manuel D’Utilisation

s

AC75_ATC_V01.002

Page 44 of 569

10/30/06

Confidential / Released

The parameter can only be used if the serial interface is enabled. 

Due to the command syntax, you need to enter parameter 

, followed by 

 is only a

placeholder and has no effect. See examples below. 
[0]

Placeholder for 

 as stated above. 

1

ME resets and restarts to full functionality. After reset and restart, PIN 1

authentication is necessary (

). If autobauding is enabled, it is recom-

mended to wait 3 to 5 seconds before entering the first AT command. For

details on autobauding refer to Section 

. 

• The settings made with 

 apply to both serial interfaces ASC0 and ASC1. 

• CYCLIC SLEEP mode cannot be activated or resumed as long as data are buffered in one of the output buff-

ers of the ME (ASC0 or ASC1). This should be taken into account, because RTS may be unintentionally

asserted if, for example, one of the following scenarios occurs: 

a) Hardware flow control is set in the ME (

3), but not in the host application (RTS/CTS handshake).

b) The two serial interfaces ASC0 and ASC1 are connected, but one of them is released, e.g. after closing or

deactivating the application connected to this interface. 

In cases a) and b) data sent by the ME, such as URCs or outstanding AT command responses, will be buff-

ered in the output buffer of this interface, signalized by the active RTS line until the buffer is emptied. 

Therefore, for CYCLIC SLEEP mode to work properly take care that the following requirements be met: Be

sure that data sent by the ME are collected on both interfaces. Activate hardware flow control on ME (TA) and

application side (TE). Avoid releasing one of the interfaces if any URCs are likely to occur on this interface. 

• In Multiplex mode, the CFUN profile is shared by all multiplexer channels. 
• If the ME is in Multiplexer mode, it is not recommended to activate SLEEP mode with 

. The

best approach to properly control SLEEP mode in this case is to issue the PSC messages described in 

,

Section "Power saving control". 

• If the host application uses the USB interface, power saving must be configured both on the AC75 module

and on the USB host, i.e. the USB host must be set to Suspend mode (usually Selective or Global Suspend).

Otherwise, if you change only the 

 parameters, the selected 

 level will be accepted but the

active USB keeps the module alive and thus prevents power saving until the USB plug is disconnected. Vice

versa, if the module is in SLEEP mode restarting the USB will cause the module to stop power saving

although the selected CFUN level does not change. 

• When a circuit-switched call is in progress, 

=7 or 9 can be activated without terminating the call. How-

ever, setting 

=0 during a circuit-switched call immediately disconnects this call. 

• To check whether power saving is on, you can query the status with the read command AT+CFUN? only if

the module is in full functionality mode or in CYCLIC SLEEP mode. If available, you can also take advantage

of the status LED controlled by the SYNC pin (see 

 and 

). With 

 you can select differ-

ent modes of LED signalization during SLEEP modes (see Section 

 for details). However, the module can wake up temporarily from power saving without leaving its

CYCLIC SLEEP mode (without changing +CFUN "

"), e.g. for a network scan after a loss of radio cov-

erage, or after receipt of serial data during CYCLIC SLEEP mode. During this "temporary wakeup state" the

LED will operate as if the ME was in full functionality mode. 

• Recommendation: In NON-CYCLIC SLEEP mode, you can set an RTC alarm to wake up the ME and return

to full functionality. This is a useful approach because, in this mode, the AT interface is not accessible. 

A wake-up event is any event that causes the ME to draw more current. Depending on the selected mode, the

wake-up event either switches the SLEEP mode off and takes the ME back to full functionality 

=1, or

activates the ME temporarily without terminating the selected SLEEP mode. 

Definitions of the state transitions described in Table 

: 

<rst>

(num)