ms744l2.txt
;************************************************************************************************
; LISTING 2 - SUBROUTINE FOR PSEUDO INTERRUPT CODE
;
; "Interfacing switches and relays to the real world in real time," EDN, June 7, 2001, pg 135
;
; http://www.ednmag.com/ednmag/reg/2001/060701/13ms744.htm
;************************************************************************************************

Interrupt Servicing Subroutine  (Only called when CH\ = Low)

1 New_Port:	Set EN\ pin Bit Low
2 Read Port Data
3 Store Port_Data in Port_P
4 Set EN\ pin bit High (Reset CH\ = High)
5 Return from Check_Port service subroutine with new Port_P data ready for main program

 Main_P		continue program prior to interrupt.
{do some thing with the new port data when required}