BC352239A Datasheet, PDF (50/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Device Terminal Descriptions
8.2.4 Clock Start-Up Delay
BlueCore3-Multimedia External 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, BlueCore3-Multimedia External 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 BlueCore3-Multimedia External as low as possible.
BlueCore3-Multimedia External 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 8.12: Actual Allowable Clock Presence Delay on XTAL_IN vs. PS Key Setting
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
Production Information
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