1. RS232 serial port:
The RS232 serial port is used for debugging. Before using it, connect the RS232_RX, RS232_TX, and
GND terminals of VT310 to the TXD, RXD, and GND terminals of the DB-9 serial port connector
respectively, and then use an RS232-to-USB adaptation cable to connect to the DB-9 serial port
connector.
2. Digital input (DI for short):
DI can detect the switch status, for example, whether the button is pressed down and whether the switch
is in the ON or OFF position. VT310 supports configurable pull-up resistance. By default, DI has 10 kΩ of
resistance pulled down to GND. When pull-up resistance is configured for DI, 20 kΩ of resistance is pulled
up to the power voltage. When using DI, you need to determine whether pull-up resistance is used.
The following figure shows the external circuit when pull-up resistance is not used for DI:
The following figure shows the external circuit when pull-up resistance is used for DI:
