SAN3010
13 Appendix C: Sample Software listing
MCS-51 MACRO ASSEMBLER
09/09/96
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0000
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0002
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0003
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0090
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0080
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KEY
SOURCE
; (c) Austria Mikro Systeme International AG AMS
; J.Janisch / telecom applications
; Program name:
KEY.ASM
; Version:
A01
; Date:
1996-09-09
; Author:
J.Janisch / Telecom Applications
;
; User program for 8051 interface to SA253x for key entry via
; microcontroller
; Application Note AN3010
; Program code is at Address 4000 HEX
;
; Reference for calculations:
; Clock Frequency of Microcontroller (80C31) = 11.0592 MHz
;
--> 1 machine cycle = 12 clock cycles = 1.085 us
;
; Decoder Logic:
; Port1:
; P1.7 : active low input; detects rising edge of C1 OR C2
;
should be set high by any output command to port 1
; P1.6 : not used
; P1.5 : not used
; P1.4 : forces selected row/column high or low
; P1.3 : when high, disables all rows/columns (high Z)
; P1.2 : row / column selector MSB
; P1.1 : row / column selector
; P1.0 : row / column selector LSB
;
;
P1.2 P1.1 P1.0
select:
;
0
0
0
row 1
;
0
0
1
row 2
;
0
1
0
row 3
;
0
1
1
row 4
;
1
0
0
column 1
;
1
0
1
column 2
;
1
1
0
column 3
;
1
1
1
column 4
;
Row1
Row2
Row3
Row4
Col1
Col2
Col3
Col4
ForceHi
ForceLo
equ
equ
equ
equ
equ
equ
equ
equ
equ
equ
0
1
2
3
4
5
6
7
90H
80H
7/13
sames
SAMES [ SAMES ]
