42
BIOS AND DRIVER SETTING
©Vecow VIG-100 User Manual
4.2 COM Port
There is some necessary configuration before user starts COM Port transmission.
For example, to set COM Port 1 as RS232 mode, please follow the steps as
below:
1.
Export GPIO 92, 71, 91 pins
3.
Follow the truth table to set COM Port 1 mode pin to "High, Low & Low."
(RS232 mode)
2.
Set GPIO 92, 71, 91 as output pins
Mode
Mode Pin 0
Mode Pin 1
Mode Pin 2
COM Port 1 (/dev/ttymxc2)
GPIO 92
GPIO 71
GPIO 91
COM Port 2 (/dev/ttymxc4)
GPIO 87
GPIO 83
GPIO 81
COM Port 3 (/dev/ttymxc6)
GPIO 88
GPIO 84
GPIO 70
COM Port 4 (/dev/ttymxc7)
GPIO 72
GPIO 69
GPIO 79
Figure 4-2-1: COM Port mode GPIO pin mapping and device name
Mode
Mode Pin 0
Mode Pin 1
Mode Pin 2
Loop Back
Low
Low
Low
RS232
High
Low
Low
RS485
Low
High
Low
RS422(5-wire)
High
High
Low
RS422(9-wire)
Low
Low
High
Figure 4-2-2: COM Port mode truth table
