Using The Sync Pin To Control A Status Led; Figure 35: Led Circuit (Example) - Siemens AC75 Hardware Interface Description

AC75 Hardware Interface Description
Strictly confidential / Preliminary
3.17.2

Using the SYNC Pin to Control a Status LED

As an alternative to generating the synchronization signal, the SYNC pin can be configured
to drive a status LED that indicates different operating modes of the AC75 module. To take
advantage of this function the LED mode must be activated with the AT^SSYNC command
and the LED must be connected to the host application. The connected LED can be operated
in two different display modes (AT^SSYNC=1 or AT^SSYNC=2). For details please refer to
[1].
Especially in the development and test phase of an application, system integrators are
advised to use the LED mode of the SYNC pin in order to evaluate their product design and
identify the source of errors.
To operate the LED a buffer, e.g. a transistor or gate,
must be included in your application. A sample circuit
is shown in Figure 35. Power consumption in the LED
mode is the same as for the synchronization signal
mode. For details see Table 26, SYNC pin.

Figure 35: LED Circuit (Example)

AC75_HD_V00.202 Page 76 of 120
s
27.04.2006