CP3BT23_14 Datasheet, PDF (103/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CP3BT23
www.ti.com
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
15.3 LMX5251 POWER-UP SEQUENCE
To power-up a Bluetooth system based on the CP3BT23 and LMX5251 devices, the following sequence
must be performed:
1. Apply VDD to the LMX5251.
2. Apply IOVCC and VCC to the CP3BT23.
3. Drive the RESET# pin of the LMX5251 high a minimum of 2 ms after the LMX5251 and CP3000
supply rails are powered up. This resets the LMX5251 and CP3BT23.
4. After internal Power-On Reset (POR) of the CP3BT23, the RFDATA pin is driven high. The RFCE,
RFSYNC, and SDAT pins are in TRI-STATE mode. Internal pullup/pull-down resistors on the
CCB_CLOCK (SCLK), CCB_DATA (SDAT), CCB_LATCH (SLE), and TX_RX_SYNC (RFSYNC) inputs
of the LMX5251 pull these signals to states required during the power-up sequence.
5. When the RFDATA pin is driven high, the LMX5251 enables its oscillator. After an oscillator start-up
delay, the LMX5251 drives a stable 12-MHz BBP_CLOCK (BBCLK) to the CP3BT23.
6. The Bluetooth baseband processor on the CP3BT23 now directly controls the RF interface pins and
drives the logic levels required during the power-up phase. When the RFCE pin is driven high, the
LMX5251 switches from “power-up” to “normal” mode and disables the internal pull-up/pull-down
resistors on its RF interface inputs.
7. In “normal” mode, the oscillator of the LMX5251 is controlled by the RFCE signal. Driving RFCE high
enables the oscillator, and the LMX5251 drives its BBP_CLOCK (BBCLK) output.
Figure 15-9. LMX5251 Power-Up Sequence
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Bluetooth Controller 103