DFF036_JOYTEST.md

Write to all 4 joystick-mouse counters at once

Mouse counter write test data:

Bit	15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00
JOY0DAT	Y7	Y6	Y5	Y4	Y3	Y2	Y1	Y0	X7	X6	X5	X4	X3	X2	X1	X0
JOY1DAT	Y7	Y6	Y5	Y4	Y3	Y2	Y1	Y0	X7	X6	X5	X4	X3	X2	X1	X0