BC41B143A-DS-003PC Datasheet, PDF (47/94 Pages) List of Unclassifed Manufacturers – BlueCore 4-ROM Plug-n-Go Single Chip Bluetooth v2.0 + EDR System

Device Terminal Descriptions
10.2.4 Clock Start-Up Delay
BlueCore4-ROM Plug-n-Go hardware incorporates an automatic 5ms delay after the assertion of the system clock
request signal before running firmware. This is suitable for most applications using an external clock source. However,
there may be scenarios where the clock cannot be guaranteed to either exist or be stable after this period. Under these
conditions, BlueCore4-ROM Plug-n-Go firmware provides a software function which will extend the system clock
request signal by a period stored in PSKEY_CLOCK_STARTUP_DELAY. This value is set in milliseconds from
5-31ms.
This PS Key allows the designer to optimise a system where clock latencies may be longer than 5ms while still keeping
the current consumption of BlueCore4-ROM Plug-n-Go as low as possible. BlueCore4-ROM Plug-n-Go will consume
about 2mA of current for the duration of PSKEY_CLOCK_STARTUP_DELAY before activating the firmware.
Actual Allowable Clock Presence Delay on XTAL_IN vs. PSKey Setting
30.0
25.0
20.0
15.0
10.0
5.0
0.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
PSKEY_CLOCK_STARTUP_DELAY
Figure 10.4: Actual Allowable Clock Presence Delay on XTAL_IN vs. PS Key Setting
BC41B143A-ds-003Pc
Advance Information
© Cambridge Silicon Radio Limited 2005
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