1 All camera support files:
2 * are allowed use of registers 21-25
3 * must have a 'shutterrelease' subroutine and the 'ret' instruction as their final instruction
4 * must use 'irport' to identify the port to which the IR LED is attached
5 * must use 'irpin' to identify the pin of 'irport' to which the IR LED is attached