LOGO Robot Demo

Here’s an early demo of the other robot I’ve been working on.  This is the beginning of a LOGO “turtle” robot… a robot that follows instruction that tell it how to draw a picture.  It drives around on a sheet of paper leaving an ink trail with its pen.  I’ve written and debugged almost all of the verilog code, I just have to build its body and wire up some electronics.  In the video, it’s executing this program:

SET    r0, 1    ; initial box size
SET    r1, r7   ; number of rings
drawbox:
PD
FW     r0
R      90
FW     r0
R      90
FW     r0
R      90
FW     r0
PU

FW     1        ; Move to SW corner
L      90
FW     1
R      180      ; Face North

INC    r0
INC    r0       ; boxsize += 2

DEC    r1
JNZ    r1, drawbox

END


The above program assembles the following machine code:
6001 //SET r0, 1
6307 //SET r1, r7
5000 //PD
0800 //FW r0
2009 //R 90
0800 //FW r0
2009 //R 90
0800 //FW r0
2009 //R 90
0800 //FW r0
4000 //PU
0001 //FW 1
3009 //L 90
0001 //FW 1
2012 //R 180
7000 //INC r0
7000 //INC r0
8001 //DEC r1
B202 //JNZ r1, addr[2]
C000 //END