LG KE520 Service Manual page 43

3. Circuit Description
3.5.3 WLAN + Bluetooth Module circuit Description
WLAN + Bluetooth Module uses two kinds of external voltages, which are supplied from Battery and
ABB.
- Sleep Clock (SLEEP_CLK)
WLAN + Bluetooth Combo Module uses a 32.768kHz Clock as a sleep clock source. The clock source
is shared with WLAN in Combo Module. It is supplied from ABB.
- System Clock (CLK_IP)
WLAN + Bluetooth Combo Module uses a 26MHz oscillator as a System clock source. The clock
source is shared with WLAN in Combo Module. It is supplied from 26MHz oscillator. SYS_CLK_REQ
go to HIGH then TCXO LDO ACTIVE, 26MHz oscillator ON.
- UART Interface
Bluetooth uses UART3 for baseband data interface. 4 signal lines are used, and are connected to
DBB.
Signal level is determined to be 1.8V for data 1, and 0V for data 0.
HCI_CTS : HCI UART Clear to Send, Active-low signal
HCI_RTS : HCI UART Request to Send, Active-low signal
HCI_RX : HCI UART Serial Data Input.
HCI_TX : HCI UART Serial Data Output.
- Bluetooth Reset
This should be ON for the first time and is controlled by DBB.
When Bluetooth is working on, this pin should be high level(1.8V).
- SDIO Interface
WLAN uses SDIO for baseband data interface. 6 signal lines are used, and are connected to DBB.
Signal level is determined to be 1.8V for data 1, and 0V for data 0.
SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3, SDIO_CMD, SDIO_CLK
3.5.4 Bluetooth Block Diagram
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