Download BV4618 User Guide Introduction

Physical Interfacing
This device has no less than three interface options:
1) Serial via Microcontroller or conversion device, e.g. USB to Serial or UART
2) Serial via RS232 (Old PC Com Port) e.g. + - 12V
3) I2C
Only one interface at a time can be used and this is detected on reset. The default
is serial via microcontroller. When pin 4 is connected this is detected as serial via
RS232 and when the I2C is connected this is detected as I2C. The detection process is
automatic.
Serial Via Microcontroller (UART)
This option uses pins 1,2,3 and 5 of the serial interface. This interface it to the
left hand side of the controller and pin 1 is marked on the PCB.
When connecting to a Microcontroller the TX pin on the microcontroller UART goes to
the RX pin on the BV4618 and the RX pin on the microcontroller goes to the TX pin on
the BV4618.
The voltage can range between 3V and 5V, however if 3.3V logic is being used then
make sure that the LCD display will work on this low voltage. At the time of writing
3.3V LCD displays are rare and expensive compared to the 5V types.
Serial Via RS232
The BV4618 can accept plus and minus 12V on pin 4 of the interface, it will also
invert that signal so as to be compatible with the microcontroller interface. The
device does NOT put out plus and minus 12V but most RS232 interfaces will tolerate
this. Again the output is inverted because the RS232 describes an inverted signal.
RS232 pin3 (TX) >> BV4618 Pin 4 (RTS)