MC45 Hardware Interface Description
P R E L I M I N A R Y
MC45_HD_01_V00.02a
Page 59 of 90
12.08.2002
3.8.2.2 Using the SYNC pin to control a status LED
As an alternative to generating the synchronization signal, the SYNC pin can be used to
control a status LED on your application platform.
To avail of this feature you need to set the SYNC pin to mode 1 by using the AT^SSYNC
command. For details see the "AT Command Set".
When controlled from the SYNC pin the LED can display the functions listed in Table 17.
Table 17: Coding of the status LED
LED mode
Operating status
Off
MC45 is off or run in SLEEP, Alarm or Charge-only mode
600 ms On / 600ms Off
No SIM card inserted or no PIN entered, or network search in
progress, or ongoing user authentication, or network login in
progress.
75 ms On / 3 s Off
Logged to network (monitoring control channels and user
interactions). No call in progress.
75 ms on / 75 ms Off / 75 ms On /
3 s Off
One or more GPRS contexts activated.
Flashing
Indicates GPRS data transfer: When a GPRS transfer is in
progress, the LED goes on within 1 second after data packets
were exchanged. Flash duration is approximately 0.5 s.
On
Depending on type of call:
Voice call:
Connected to remote party.
Data call:
Connected to remote party or exchange of
parameters while setting up or disconnecting a call.
LED Off = SYNC pin low. LED On = SYNC pin high (if LED is connected as illustrated in Figure 23)
To operate the LED a buffer, e.g. a transistor or gate,
must be included in your application. A sample
configuration can be gathered from Figure 23. Power
consumption in the LED mode is the same as for the
synchronization signal mode. For details see Table
19, SYNC pin.
Figure 23: LED Circuit (Example)
