Siemens SXG 75 Service Repair Documentation page 65

13. Bluetooth
SXG75 contains a BCM2004 Bluetooth RF module. The BCM2004 is powered from VREG_MSMP
(2.6V) for the digital interface, and VREG_AUX2 (2.85V) for the RF/core stages. The IC contains an
internal regulator which regulates VREG_AUX2 down to VDD_BT (1.8V).
The Bluetooth baseband processor is contained within the MSM6250. The dedicated Bluetooth
interface between the two devices consists of a synchronous serial bus to transfer configuration and
control messages, a synchronous serial bus to transfer channel data and logic control signals.
Interface signal functions are described below:
Signal
BT_ENABLE
BT_CLK
BT_DATA
BT_TX_RX_N
BT_SDST
BT_SBDT
BT_SBCK
BUFF_TCXO_BT
Bluetooth module interface signals
Technical Documentation
TD_Repair_L3_SXG75_R1.0.pdf
Function
Logic input from MSM6250 GPIO.
This signal was previously used to enable the VDD_BT regulator. On the
final version of Wolf 5 the control is no longer used, and the regulator is
permanently enabled by pull-up resistor R1607.
Logic output to MSM6250 Bluetooth interface. System clock, 12 MHz
clock output derived from the BUFF_TCXO_BT reference.
Logic I/O to MSM6250 Bluetooth interface. Bi-directional Tx and Rx
Channel data interface signal.
Logic input from MSM6250 Bluetooth interface. Multi-Purpose Pin: Rx Slot
- Rx_Enable and synchronization detection; Tx Slot - Tx_En and Tx path
data transfer indication.
Logic input from MSM6250 Bluetooth interface. Serial interface mode
control.
Logic IO to MSM6250 Bluetooth interface. Serial interface data.
Logic input from MSM6250 Bluetooth interface. Serial interface clock.
19.2MHz master clock input.
The TCXO clock is buffered by the single-gate inverter, D1300. The in-
verter is configured to operate as a linear buffer by C1332/R1310. The
buffer is only enabled when the input VREG_AUX2 is high. This prevents
the clock from being applied when Bluetooth is disabled.
Company Confidential
2006©BenQ
Release 1.0
01/2006
Page 65 of 73