CP3BT23_14 Datasheet, PDF (104/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CP3BT23
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
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15.4 LMX5252 POWER-UP SEQUENCE
A Bluetooth system based on the CP3BT23 and LMX5252 devices has the following states:
• Off—When the LMX5252 enters Off mode, all configuration data is lost. In this state, the LMX5252
drives BPOR low.
• Power-Up—When the power supply is on and the LMX5252 RESET# input is high, the LMX5252
starts up its crystal oscillator and enters Power-Up mode. After the crystal oscillator is settled, the
LMX5252 sends four clock cycles on BRCLK (BBCLK) before driving BPOR high.
• RF Init—The baseband controller on the CP3BT23 now drives RFCE high and takes control of the
crystal oscillator. The baseband performs all the needed initialization (such as writing the registers in
the LMX5252 and crystal oscillator trim).
• Idle—The baseband controller on the CP3BT23 drives RFDATA low when the initialization is ready.
The LMX5252 is now ready to start transmitting, receiving, or enter Sleep mode.
• Sleep—The LMX5252 can be forced into Sleep mode at any time by driving RFCE low. All
configuration settings are kept, only the Bluetooth low power clock is running (B3k2).
• Wait XTL—When RFCE goes high, the crystal oscillator becomes operational. When it is stable, the
LMX5252 enters Idle mode and drives BRCLK (BBCLK).
Figure 15-10. LMX5252 Power States
104 Bluetooth Controller
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