Sterling-LWB(5) SD Card Board
User Guide
Embedded Wireless Solutions Support
Center: http://ews-support.lairdtech.com
www.lairdtech.com/wireless
330-0245-R1.1
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Table 2: Connector J3 pinout
J3 Pin
Number
Pin Name
Description
1
VIN_EXT
External Supply Voltage
2
VCC_IO_EXT
External I/O Voltage Supply
3
BT_HOST_WAKE
Bluetooth host wake signal from module
4
BT_PCM_CLK
PCM Clock Input
5
BT_PCM_SYNC
PCM Frame Synch Signal
6
BT_UART_CTS_HST_RTS
Module Bluetooth UART CTS signal (host RTS signal)
7
BT_PCM_IN
PCM Input Signal
8
BT_UART_TXD_HOST_RXD
Module Bluetooth UART transmit pin (host receive pin)
9
BT_PCM_OUT
PCM Output Signal
10
BT_UART_RXD_HST_TXD
Module Bluetooth UART receive pin (host transmit pin)
11
WLREG_ON
Wi-Fi Enable
12
NC
Not Connected
13
BT_REG_ON
Module Bluetooth enable signal
14
BT_UART_RTS_HST_CTS
Module Bluetooth UART RTS signal (host CTS signal)
15
BT_DEV_WAKE
Bluetooth device wake signal from host
16
GND
Ground
Note:
Pin Layout is the same for the Sterling-LWB5 version of the SD Card
3.2.
Development Board Power
The Sterling-LWB & Sterling-LWB5 SD card boards provide two possible sources for powering the board 3.3V.
Power can be provided from an external power supply on J5 or from the SD card bus (Pin 4). Jumper J7 is used to
select which power supply is used. Sterling-LWB is setup in the 3.3V position when shipped.
Note:
The Sterling-LWB5 SD Card will need to be powered with a secondary power supply at 1.8V to J3 Pin 2
(VCC_IO_EXT) and Pin 16 (GND). 3.3V is for WiFi and 1.8V is for I/O pins. The Sterling-LWB and Sterling-LWB5 SD
Cards utilize the same PCBA and because of this the silkscreen will show 3.3V on Jumper J4. Sterling-LWB
supports both VIO voltages of 3.3V and 1.8V. Sterling-LWB5 only operates at VIO of 1.8V.
To decide which power supply is best for you, check with the manufacturer of your host development board to
determine the maximum current for the power supply used for the SD card slot. If this is too low, consider
powering the board externally. See the Sterling-LWB and Sterling-LWB5 module datasheets for power supply
requirements of the module in various operating modes.
