User's Manual Part 2

5.1: How to Use the Stop Mode Feature Chapter 5: Power Save Modes

Chapter 5

Power Save Modes

The Serial Port Adapter is optimized to consume as little power as possible.

However, the deepest power save mode, called stop mode, is not turned on by de-

fault. Instead an AT command (AT*AMPM) is available to allow the host system to

turn on the stop mode feature.

When the Serial Port Adapter is in stop mode:

• It can accept incoming connections over Bluetooth.

• The host system cannot send data to the Serial Port Adapter.

The Serial Port Adapter will only enter stop mode if:

• The stop mode feature has been turned on using the AT*AMPM AT

command

•

The DSR pin on the Serial Port Adapter is not active.

•

If there is no Bluetooth connection.

• If the "Always connected" feature has not been turned on.

The Serial Port Adapter will exit mode if:

•

A Bluetooth connection is established from a remote device.

• The host system moves the DSR pin from non-active to active.

Note: The Serial Port Adapter needs 10 ms to leave stop mode. As a con-

sequence the host system must not send data to the Serial Port Adapter

until 10 ms after the host system has activated the DSR pin.

5.1 How to Use the Stop Mode Feature

If your device only acts as a server (accepts incoming connections), the stop mode

feature can be used without the host having to toggle the DSR pin before sending

data to the Serial Port Adapter. The reason for this is that while in stop mode, the

Serial Port Adapter can accept incoming connections. In addition, when the Blue-

tooth connection is established the Serial Port Adapter automatically leaves stop

mode and only returns to stop mode after the Bluetooth connection has been dis-

connected. However, in this scenario, it is important that the host system keeps

the DSR pin in the non-active state at all times. Otherwise the Serial Port Adapter

will not enter stop mode at all.

If your device acts as a client (establishes connections) or client and server, the stop

mode feature cannot be used without the use of the DSR pin. The reason for this is

that once in stop mode, the Serial Port Adapter has to be told to leave stop mode

before the host system can send data to the Serial Port Adapter. When the host

system has nothing to send to the Serial Port Adapter, it may set the DSR pin to

the non-active state to tell the Serial Port Adapter that it may enter stop mode if it

is able to.