Rainbow Electronics DAB-WLS-C21 (BlueTooth) - Manual (Page 14)

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DSH_BTM402_0v9 BISM2 PA Data Sheet.DOC © 2007 EZURiO Ltd 14
7.4 Multipoint Firmware
For multipoint operation, the same hardware can be loaded with multipoint software. Whereas the
firmware for single point ‘AT’ communication only allows one connection to be active at any one time,
using multipoint firmware allows a number of simultaneous connections to be made and maintained.
It also allows connections to multiple profiles to one or more devices. Multipoint firmware should be
seen as a concept of channels instead of slave connections.
When operating in Bluetooth multipoint mode, the resources and bandwidth of a Bluetooth master
device are shared amongst the different connected devices. This has an impact on the maximum
throughput to any one device. If multiple device connections are maintained it also impacts on the
memory resources and device database within the Bluetooth stack. Designers should be aware of
these restrictions when using multipoint configurations. In most cases better latency and power
consumption can be achieved by polling or fast data transfer rather than by maintaining concurrent
connections.
In general, multipoint connections are viable for up to three connections, at which point memory
constraints start to limit the actual data rates. For more than three connections, other connection
schemes offer a more efficient approach. Contact EZURiO for more information.
7.5
OTA (Over the Air) Configuration
When the BISM II PA has its remote AT parser enabled, its settings can be remotely controlled by a
master unit (see register S536). This places the slave unit’s AT parser in remote mode providing
over the air configuration. This mode is of use for remote sensor applications, where no host
processor is required to control the slave Bluetooth unit.
7.6 Boot modes
The module has the capability of booting into 1 of 7 modes. Currently only Boot Mode 1 is supported.
Boot Mode 1 is default and gives functionality equivalent to the BISM1 module.
These modes will specify different PSKEY settings to allow for different basic operation. Please
contact EZURiO for further information.
8. Low Power Modes
The current drain from the Vcc power input line is dependent on various factors. The three most
significant factors are the voltage level at Vcc, UART baud rate and the operating mode.
The hardware specification for the PA module allows for a voltage range of 3.6V to 5.0V at Vcc.
The UART baud rate has a bearing on power drain because as is normal for digital electronics, the
power requirements increase linearly with increasing clocking frequencies. Hence higher baud rates
result in a higher current drain.
Finally with regards to operating mode the significant modes are; idle, waiting for a connection,
inquiring, initiating a connection and connected. With connected mode, it is also relevant to
differentiate between no data being transferred and when data is being transferred at the maximum
rate possible.
The operating mode can best be described by stating the AT commands required to enter that mode.
In addition, there are certain S Registers which have a direct impact on power consumption, which
are described next.
S Registers 508 to 511, which specify the page and inquiry scan intervals and windows, can be used
to adjust the average current drain when in discoverable and or connectable modes. Registers 508
and 509 specify the interval and window for page scans and registers 510 and 511 specify the
interval and window for inquiry scans. Register pairs 508/509 and 510/511 describe duty cycles when
the module goes into scan modes. It is while scanning that the highest current draw occurs. The
average current draw is determined by simple arithmetic using the values stored in the 508/509 and
510/511 register pairs.