User's Manual

Class 1 Bluetooth v2.0 Module
User’s Guide
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CONN-GUIDE-BT730_v0.9
5.4 General Purpose I/O and ADC
5.4.1 GPIO
Seven lines of programmable bi-directional input/outputs (I/O) are provided that can be accessed either
via the UART port, or Over The Air (OTA) from a second Bluetooth unit. These can be used as data
inputs or to control external equipment. By using these in OTA mode, a BT730 module can be used for
control and data acquisition without the need for any additional host processor. Each of the GPIO[3:9]
ports can be independently configured to be either an input or output. A selection of ports can be
accessed synchronously.
The ports are powered from VCC. The mode of these lines can be configured and the lines are accessed
via S Registers 623 to 629.
5.4.2 ADC
The BT730 provides access to two 8-bit ADCs (Analogue 0 and 1). These provide an input range of 0 mV
to 1,800 mV, which can be read using the S registers 701 and 702.
Suitable external scaling and over-voltage protection should be incorporated in your design. The module
provides five samples per second at the UART with a baud rate of 115,200 or above.
6. AT COMMAND SET REFERENCE
6.1 Introduction
This document describes the protocol used to control and configure the following Laird Technologies
Bluetooth devices:
 BT730-SA
 BT730-SC
The protocol is similar to the industry standard Hayes AT protocol used in telephony modems which is
appropriate for cable replacement scenarios, as both types of devices are connection oriented. The
telephony commands have been extended to make the Laird device perform the two core actions of a
Bluetooth device, which is make/break a connection and Inquiry. Other AT commands are also provided
to perform ancillary functions, such as pairing, trusted device database management, and S register
maintenance.
Similar to telephony modems, the Laird device powers up in an unconnected state and only responds via
the serial interface. In this state, the Laird device does not respond to Bluetooth inquiries. Then, just like
controlling a modem, the host can issue AT commands which map to various Bluetooth activities. The
command set is extensive enough to allow a host to make connections which are authenticated and/or
encrypted or not authenticated and/or encrypted or any combination of these. Commands can be saved,
so that on a subsequent power-up the device is discoverable or automatically connects.
The device has a serial interface which can be configured for baud rates from 1200 up to 921600 and an
RF communications end point. The latter has a concept of connected and unconnected modes and the
former has a concept of command and data modes. This leads to the matrix of states shown in Table 6-1.