User's Manual

BL652
Datasheet
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 UART
Required for loading your smartBASIC application script during development (or for subsequent firmware
upgrades (except JTAG for FW upgrades and/or Flash Cloning of the smartBASIC application script). Add
connector to allow interfacing with UART via PC (UART–RS232 or UART-USB).
 UART_RX and UART_CTS
SIO_8 (alternative function UART_RX) is an input, set with internal weak pull-up (in firmware). The pull-up
prevents the module from going into deep sleep when UART_RX line is idling.
SIO_7 (alternative function UART_CTS) is an input, set with internal weak pull-down (in firmware). This pull-
down ensures the default state of the UART_CTS will be asserted which means can send data out of the
UART_TX line. Laird recommends that UART_CTS be connected.
 nAutoRUN pin and operating mode selection
nAutoRUN pin needs to be externally held high or low to select between the two BL652 operating modes at
power-up:
– Self-contained Run mode (nAutoRUN pin held at 0V).
– Interactive / development mode (nAutoRUN pin held at VCC).
Make provision to allow operation in the required mode. Add jumper to allow nAutoRUN pin to be
held high or low (BL652 has internal 13K pull-down by default) OR driven by host GPIO.
 I2C
It is essential to remember that pull-up resistors on both I2C_SCL and I2C_SDA lines are not provided in the
BL652 module and MUST be provided external to the module as per I2C standard.
 SPI
Implement SPI chip select using any unused SIO pin within your smartBASIC application script then SPI_CS is
controlled from smartBASIC application allowing multi-dropping.
 SIO pin direction
BL652 modules shipped from production with smart BASIC runtime engine FW, all SIO pins (with default
function of DIO) are mostly digital inputs (see Pin Definitions Table2). Remember to change the direction SIO
pin (in your smart BASIC application script) if that particular pin is wired to a device that expects to be driven
by the BL652 SIO pin configured as an output. Also, these SIO pins have the internal pull-up or pull-down
resistor-enabled by default in firmware (see Pin Definitions Table 2). This was done to avoid floating inputs,
which can cause current consumption in low power modes (e.g. StandbyDoze) to drift with time. You can
disable the PULL-UP or Pull-down through their smartBASIC application.
Note: Internal pull-up, pull down will take current from VCC.
 SIO_02 pin and OTA smartBASIC application download feature
SIO_02 is an input, set with internal pull-down (in FW). Refer to latest firmware release documentation on
how SIO_02 is used for Over the Air smartBASIC application download feature. SIO_02 pin has to be pulled
high externally to enable the feature. Decide if this feature is required in production. When SIO_02 is high,
ensure nAutoRun is NOT high at same time; otherwise you cannot load the smartBASIC application script.
 NFC antenna connector
To make use of the Laird flexi-PCB NFC antenna, fit connector:
Description: FFC/FPC Connector, Right Angle, SMD/90d,Dual Contact,1.2mm Mated Height
Manufacturer: Molex
Manufacturers Part number: 512810594