B&B Electronics USB-4751/4751L Manual De Usuario

The USB Module is equipped with a LED indicator to show the current 
status of the device. When you plug the USB device into the USB port, 
the LED indicator will blink five times and then stay lit to indicate that it 
is on. Please refer to the following table for detailed LED indicator status 
information.

PA<0~7, 
10~17>

GND Input/Out-

put

Digital input/ output port A, channel 
0~7 & channel 10~17.

PB<0~7, 
10~17>

GND Input/Out-

put

Digital input/ output port B, channel 
0~7 & channel 10~17.

PC<0~7, 
10~17>

GND Input/Out-

put

Digital input/ output port C, channel 
0~7 & channel 10~17.

+5V_OUT

GND Output

+5V DC power

C<1,2>_Out

GND Output

Output pins of counter/ timer 1 and 2

C<1,2>_Gate

GND Input

Gate control pins of counter/ timer 1 
and 2

C<1,2>_In

GND Input

External clock source of counter/ timer 
1 and 2

INT_Out

GND Output

Interrupt output. This pin changes to 
logic 1 whenever the
USB-4751  generates an interrupt, and 
returns to logic 0 when the interrupt is 
cleared.

GND

-

-

Digital ground

On

Device ready for work

Off

Device not ready to work

Slow Blinking (5 times)

Device initialization

Fast Blinking
(Depends on data transfer speed).

Device working