mikroişlemci finaline çalışıyorum

Write a MC68HC11 Assembly Language Program. The program will be implemented as an IAR Embedded Workbench Project. The project must:
o Implement the delay using a subroutine – the delay must be variable – the amount of the delay must be controlled with a parameter (argument) passed to the subroutine
o Include two separate files – one for main, one for delay.
o Assume a switch is connected to Port A bit 4
o Display one of two blinking patterns depending of the input seen at Port A bit 4
 PortA(4) switch closed
• PortA(3:0) = 0011
• PortA(3:0) = 1100
• Repeat
 PortA(4) switch open
• PortA(3:0) = 1111
• PortA(3:0) = 0000
• Repeat
 Unused bits of Port A must not be affected by your code. Bits which are not used by your program may be initialized as either input or output by another program.