Matrix
Matrix accepts 8 arguments.
u 1 row1,row2,row3,row4,row5,row6,row7,row8
These must be 8 numbers from 0 to 255. Each bit of these numbers represents a single pixel on the Matrix.
The least significant bit (decimal 1) represents the left-most pixel on the matrix. The first number corresponds to the bottom row.
To clear the Matrix you would send:
0b00000000
0b00000000
0b00000000
0b00000000
0b00000000
0b00000000
0b00000000
0b00000000
Or: s 1 0,0,0,0,0,0,0,0
To draw a diagonal line from the bottom left most corner, to the top right most corner would send:
0b00000001
0b00000010
0b00000100
0b00001000
0b00010000
0b00100000
0b01000000
0b10000000
Or: s 1 1,2,4,8,16,32,64,128
Note that the binary representation of this actually shows you what will is drawn on the Matrix. Albeit upside-down.