
www.national.com
32
L
11.0 Low Power Modes
The LMX9830 supports different Low Power Modes to
reduce power in different operating situations. The modular
structure of the LMX9830 allows the firmware to power
down unused modules.
The Low power modes have influence on:
■
UART transport layer
– enabling or disabling the interface
■
Bluetooth Baseband activity
– firmware disables LLC and Radio if possible
11.1 POWER MODES
The following LMX9830 power modes, which depend on
the activity level of the UART transport layer and the radio
activity are defined:
The radio activity level mainly depends on application
requirements and is defined by standard bluetooth opera-
tions like inquiry/page scanning or an active link.
A remote device establishing or disconnecting a link may
also indirectly change the radio activity level.
The UART transport layer by default is enabled on device
power up. In order to disable the transport layer the com-
mand “Disable Transport Layer” is used. Thus only the
Host side command interface can disable the transport
layer. Enabling the transport layer is controlled by the HW
Wakeup signalling. This can be done from either the Host
or the LMX9830. See also “LMX9830 Software User’s
Guide” for detailed information on timing and implementa-
tion requirements.
Figure 21. Transition between different Hardware Power Modes
11.2 ENABLING AND DISABLING UART
TRANSPORT
11.2.1 Hardware Wake up functionality
In certain usage scenarios the host is able to switch off the
transport layer of the LMX9830 in order to reduce power
consumption. Afterwards both devices, host and LMX9830
are able to shut down their UART interfaces.
In order to save system connections the UART interface is
reconfigured to hardware wakeup functionality. For a
detailed timing and command functionality please see also
the “LMX9830 Software User’s Guide”.
Table 24. Power Mode activity
Power
Mode
PM0
PM1
PM2
UART
activity
OFF
ON
OFF
Radio
activity
OFF
OFF
Scanning
Reference
Clock
none
Main Clock
Main Clock /
32.768khz
Main Clock
Main Clock
Main Clock
PM3
PM4
PM5
ON
OFF
ON
Scanning
SPP Link
SPP Link
No radio activity
Page / Inquiry Scanning
Active Link(s)
Bluetooth Radio Activity
UART Disabled
Wake-up Enabled
UART Enabled
Wake-up Disabled
All Links Released
PM0
PM1
PM3
PM5
PM4
PM2
Link Established
All Links released
Link Established
All Links released
Incoming Link
All Links released
TL Enabled
Disable TL
Disable TL
Disable TL
TL Enabled
TL Enabled
Scanning Enabled
Scanning Disabled