Specifications

MC55/56 Hardware Interface Description
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MC55/56_hd_v04.00a Page 64 of 108 24.08.2006
3.12.2 Outputs
3.12.2.1 Synchronization signal
The SYNC pin can adopt two different operating modes which you can select by using the
AT^SSYNC command. For details see also
[1].
The mode AT^SSYNC=0 (factory default) enables the SYNC signal to indicate that a
transmit burst is occurring, and hence, more current flows. The mode AT^SSYNC=1 enables
the SYNC pin to drive a status LED as described in Chapter
3.12.2.2.
The mode AT^SSYNC=0 is recommended if you want your application to use the
synchronization signal for better power supply control. Your platform design shall be such
that the incoming signal accommodates sufficient power supply to the MC55/56 module if
required because of the transmit burst. This can be achieved by lowering the current drawn
from other components installed in your application.
States of the SYNC pin if AT^SSYNC=0: High level indicates increased power consumption
during transmission. The timing of the synchronization signal is shown below.
Figure 22: SYNC signal during transmit burst
*)
The duration of the SYNC signal is always equal, no matter whether the traffic or the
access burst are active.
Transmit burst
1 Tx 577 µs every 4.616 ms
2 Tx 1154 µs every 4.616 ms
300 µs
SYNC signal
*)