User's Manual

Class 1 Bluetooth v2.0 Module
User’s Guide
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www.lairdtech.com/bluetooth
10
CONN-GUIDE-BT730_v0.9
COMPATIBILITY NOTE FOR LEGACY DEVICES
If Reset compatibility is required with BTM402 and BTM404: Reset logic must be inverted (on the host
PCB), by using suitable BJT (MMBT3904) with collector connected to Reset pin BT730 module pin 5. A
fixed 10k Ohm pull down resistor to ground (BJT input) then ensures that the BT730 module is out of
reset for the condition when host has yet to control the reset line.
Add a 10k pull-up to the host PCB on the UART_RX, otherwise the module will remain in deep sleep if
not driven to high.
Add a 10k pull-down to the host PCB on the UART_CTS that if it is not connected (which we do not
recommend) then the default state for UART_CTS input will be asserted which means can send data out
of UART_TX line.
PIO lines can be configured through software to be either inputs or outputs with weak or strong pull-ups
or pull-downs. At reset, all PIO lines are configured as inputs with weak pull-downs.
UART_RX, UART_TX, UART_CTS, UART_RTS, UART_RI, UART_DCD, and UART_DSR are all 3.3 V
level logic. For example, when RX and TX are idle they will be sitting at 3.3 V. Conversely, for
handshaking pins CTS, RTS, RI, DCD, and DSR, a 0 V is treated as an assertion.
Pin 28 (UART_RI) is active low. It is normally 3.3 V. When a remote device initiates a connection, this pin
goes low. This means that when this pin is converted to RS232 voltage levels it will have the correct
voltage level for assertion.
Pin 17 (UART_DCD) is active low. It is normally 3.3 V. When a connection is live, this pin is low. This
means that when this pin is converted to RS232 voltage levels it will have the correct voltage level for
assertion.
Pin 16 (UART_DSR) is an input, with active low logic. It should be connected to the DTR output of the
host. When the BTM730 module is in high speed mode (see definition for S Register 507), this pin should
be asserted by the host to ensure that the connection is maintained. A deassertion means that the
connection should be dropped or an online command mode is being requested.
Pin 13 (VCC_3V3 monitor) may only be used for monitoring purposes. It must not be used as a current
source.
The GPIO pins can be accessed using S Registers 623 to 629.
GPIO3 is also used for DTR output (active low).See S Register 552 and553.
Analogue 0 and 1 should not exceed 1.8 V and S Registers 701 and 702 are used to access them.