CP3BT23 Datasheet, PDF (79/260 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

15.3 LMX5251 POWER-UP SEQUENCE
15.4 LMX5252 POWER-UP SEQUENCE
To power-up a Bluetooth system based on the CP3BT23 A Bluetooth system based on the CP3BT23 and LMX5252
and LMX5251 devices, the following sequence must be per- devices has the following states:
formed:
! Off—When the LMX5252 enters Off mode, all configura-
1. Apply VDD to the LMX5251.
tion data is lost. In this state, the LMX5252 drives BPOR
2. Apply IOVCC and VCC to the CP3BT23.
low.
3. Drive the RESET# pin of the LMX5251 high a minimum ! Power-Up—When the power supply is on and the
of 2 ms after the LMX5251 and CP3000 supply rails are LMX5252 RESET# input is high, the LMX5252 starts up
powered up. This resets the LMX5251 and CP3BT23.
its crystal oscillator and enters Power-Up mode. After the
4. After internal Power-On Reset (POR) of the CP3BT23, crystal oscillator is settled, the LMX5252 sends four
the RFDATA pin is driven high. The RFCE, RFSYNC, clock cycles on BRCLK (BBCLK) before driving BPOR
and SDAT pins are in TRI-STATE mode. Internal pull- high.
up/pull-down resistors on the CCB_CLOCK (SCLK), ! RF Init—The baseband controller on the CP3BT23 now
CCB_DATA (SDAT), CCB_LATCH (SLE), and drives RFCE high and takes control of the crystal oscilla-
TX_RX_SYNC (RFSYNC) inputs of the LMX5251 pull tor. The baseband performs all the needed initialization
these signals to states required during the power-up (such as writing the registers in the LMX5252 and crystal
sequence.
oscillator trim).
5. When the RFDATA pin is driven high, the LMX5251 en- ! Idle—The baseband controller on the CP3BT23 drives
ables its oscillator. After an oscillator start-up delay, the RFDATA low when the initialization is ready. The
LMX5251 drives a stable 12-MHz BBP_CLOCK LMX5252 is now ready to start transmitting, receiving, or
(BBCLK) to the CP3BT23.
enter Sleep mode.
6. The Bluetooth baseband processor on the CP3BT23 ! Sleep—The LMX5252 can be forced into Sleep mode at
te ^{now directly controls the RF interface pins and drives any time by driving RFCE low. All configuration settings}
the logic levels required during the power-up phase. are kept, only the Bluetooth low power clock is running
When the RFCE pin is driven high, the LMX5251 (B3k2).
switches from “power-up” to “normal” mode and dis- ! Wait XTL—When RFCE goes high, the crystal oscillator
ables the internal pull-up/pull-down resistors on its RF becomes operational. When it is stable, the LMX5252
interface inputs.
enters Idle mode and drives BRCLK (BBCLK).
le ^{7. In “normal” mode, the oscillator of the LMX5251 is con-}
trolled by the RFCE signal. Driving RFCE high enables
the oscillator, and the LMX5251 drives its BBP_CLOCK
(BBCLK) output.
Any State
RESET# = Low or
Power is cycled
VDD_LMX5251
o _VCCCP3000
IOVCC_CP3000
RESET#_LMX5251
RESET_CP3000
s _RFCE
BBCLK
RFDATA
b _RFSYNC
SDAT
SCLK
O ^SLE
t_PTOR
Low
Low
High
Low
Low
Low
High
Wait for
Crystal Osc.
To Stabilize
Off
RESET# = High and
Power is On
Power-Up
Crystal Osc. Stable
Any State
After RF Init
RFCE = Low
Sleep
RFCE = High
RFCE = High
RFDATA = Don't Care
Write Registers
RF Init
Wait for
Crystal Osc.
To Stabilize
Wait XTL
LMX5251 CP3000 LMX5251
Oscillator Initialization Initialization
Start-Up
Standby
Active
Crystal Osc. Stable
Idle
LMX5251 in
Power-Up Mode
LMX5251 in Normal Mode
DS016
Figure 23. LMX5251 Power-Up Sequence
DS324
Figure 24. LMX5252 Power States
The power-up sequence for a Bluetooth system based on
the CP3BT23 and LMX5252 devices is shown in Figure 25.
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