Basys3 Counter

This example shows a simple binary counter implemented in Basm, the BondMachine assembly. The example uses the 16 Basys3 LEDs to show the counter. The counter is implemented in the file counter.basm:

%section code .romtext
    entry _start ; Entry point
_start:
    clr     r0   ; Clear the counter
loop:
    inc    r0    ; Increment the counter
    r2o    r0,o0 ; Output the counter to the LEDs
    j      loop  ; Jump back to the loop

%endsection

%meta cpdef     cpu romcode: code, ramsize:8
%meta ioatt     testio cp: cpu, index:0, type:output
%meta ioatt     testio cp: bm, index:0, type:output
%meta bmdef     global registersize:16

The connection to the leds is done in the file default_maps.json. The file maps the output o0 of the BondMachine to the 16 LEDs of the Basys3 board:

{
"Assoc" : {
	"clk" : "clk",
	"reset" : "btnC",
	"o0": "[15:0] led"
	}
}

The configuration file .config specifies all the necessary information to build the project. The BOARD_SLOW variable is set to true so the counter is visible in the LEDs.

In order to build the project, the following prerequisites must be met:

• Vivado installed and in the PATH
• The BondMachine tools installed and in the PATH
• The Basys3 board connected to the computer

To build the project and program the Basys3 board, run the following command:

make apply
make program

After some time, depending on the computer, the counter will be visible in the LEDs of the Basys3 board.