Changes
The ASIC includes the logic for an octal A/D converter, in conjunction with an external R-2R network, comparator and analogue multiplexer. Eight analogue input channels are thus available on the PCB, of which only four have connectors. This allows support for four paddles or two joysticks, with capacity for twice this many without redesigning the ASIC. The A/D is 6 bits wide, to give sufficient resolution after calibrating joysticks. It appears to the software as a bank of eight, 6 bit, read-only registers from 6808h to 680Fh, known as ADC0-7. They are updated approximately 200 times per second. The A/D inputs have an input range of 0V (data = 00) to 2.5V (data = 3Fh), and an input impedance of 180k to Vcc.
On my 464, the default values with no joystick attached are &3f,&3f,&3f,&3f,&3f,&00,&3f,&00. With a AJ-5 attached only channels 0 and 1 change. Channel 0 is the X movement and channel 1 is the Y movement.
The fire buttons on the joystick are mapped to digital joystick 0's fire 0 and fire 1.
===PAL subcarrier locking===
