There are eight general-purpose LEDs on the ECM1900.  Each is wired to the FPGA (bank 66) as shown in the table below.

LED REF DESFPGA PIN
D3AF10
D4AC14
D5AG9
D6AF8
D7AH8
D8AG8
D9AH11
D10AG11

LED Operation in HDL

The LED anodes are connected to a pull-up resistor to +3.3 V, and the cathodes wired through NMOS transistors to the FPGA I/O on Bank 66.

To operate the LEDs from FPGA gateware (HDL):

  • To turn ON an LED, the corresponding FPGA pin should be at logic 1.
  • To turn OFF an LED, the corresponding FPGA pin should be at logic 0.