ms744l1.txt
;************************************************************************************************
; LISTING 1 - SUBROUTINE FOR PSEUDO POLLING 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
;************************************************************************************************

Port Polling Subroutine

1 Check_Port:	Read Port Data
2 Store Port_Data in Port1
3 Compare Port1 with Port_P, (EX-OR Port1 with Port_P)
4 Test for Bit Changes, (No) Return from Check_Port subroutine, (Yes) continue
5 Add 1 to Count
6 Count  = N_Pass_Value, (No) Return from Check_Port subroutine, (Yes) continue
7 Set Count = 0
8 Store Port1 in Port_P
9 {do some thing with the new port data}
10 Return from Check_Port subroutine with new Port_P data for main program