Using Low Power Modes (Inquiry And - Serialio BlueSnapXP User Manual

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this will set a flag in a stored register that is read at power-up. The Power-up settings for the GPIO can also be viewed using
the "O" (other settings) command.
WARNING:
GPIO-4 is used by the system to reset stored parameters to factory defaults. If GPIO4 is pulled high on power-up, and then
toggled 3 times, all user settings will return to default values. Therefore this pin should not be used as an output, and should
not be driven high at power-up time (first 1 second of operation).
NOTE:
GPIO2 and 5 are driven by the embedded software as outputs, they can be disabled using the direction command, (to save
power, for example) and used as inputs. If set to outputs the software will override any user values.
SETTING GPIO 8-9-10-11
S*,<hexword> = MASK[11..8] VALUE[11..8]
For the upper 4 GPIO, a single word controls the mask and values, and only the lower 4 bits of each byte are used. The first
time this command is used, all 4 GPIO are driven as outputs and remain so until a power cycle. There is no powerup
command for these bits, only the interactive one. Some modules do not offer these GPIO.
Examples:
S*,0101 GPIO-8 driven HIGH.
S*,0100 GPIO-8 driven LOW.
S*,0202 GPIO-9 driven HIGH.
4. 1 Using Low Power Modes
4.1.1 Inquiry(Discovery) and Page(Connection) Windows
There are 2 timers that can be used to lower the idle Slave mode power of the radio. When not connected, the
Radio is active for a percentage of time listening to see if any other device wants to Discovery (inquire) or
Connect (page). The amount of time the radio is on is called the window, and the rate at which the process cycles
is called the interval. The interval is fixed at 0x800 (1.28seconds) with Sniff disabled, and 2.56 seconds with Sniff
enabled. The window can be adjusted. The default window is 0x200 (320 ms) or 25% duty cycle.
By lowering the window value, power can be saved at the expense of possibly missing an inquiry or page. Since
the host usually retries automatically many times, the only downside is a delay in discovery or connection time.
The minimum window for inquiry or page is 0x0012 (11.25ms). corresponding to about a 1% duty cycle.
Thus, average power can be reduced from >20ma to <5ma in standard mode, and <3ma in Sniff mode.
It is also possible (and desirable for security reasons) to completely disable inquiry. Once a host has found and
installed a device, inquiry is not needed, only page is used to make a connection.
To disable inquiry and still allow connections, set the Inquiry timer to 0 with "SI,0000".
4.1.2 SNIFF mode
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