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Fundamentals of Dot Matrix Printing
I
- - - - - - - -
Print Head
Print Head
8·Bit
7·Bit
Pin Number
(top)
Interface
Interface
•
128
64
2
•
64
32
3
32
16
4
16
8
5
•
8
4
6
•
4
2
7
•
2
8
•
not used
9
not used
not used
Based on the chart presented above, if you had a 7-bit
computer and wanted to fire pins number 1 and 4 simultaneously,
you would send CHR$(64 +8). In other words, you'd send CHR$(72):
Therein is the pattern. Thus, if you wanted to fire all the pins, using
an 8-bit computer, you'd send:
CHR$(128 + 64 + 32 + 16 + 8 + 4 + 2 + 1)
=
CHR$(255)
Control
Binary
Pin
Code
Representation
Fired
CHR$(128)
1
0 0
0
0 0
0 0
#1
CHR$( 64)
0
1
0
0
0
0
0
0
#2
CHR$( 32)
0
0
1
0
0
0
0 0
#3
CHR$( 16)
0
0 0
1
0
0
0 0
#4
CHR$(
8)
0
0
0
0
1
0
0 0
#5
CHR$(
4)
0
0 0
0
0
1
0 0
#6
CHR$(
2)
0
0 0
0
0
0
0
#7
CHR$(
1)
0
0 0
0
0
0
0
#8
CHR$(
0)
0
0
0
0
0
0
0 0
none
CHR$(255)
1
1
1
1
1
1
1
1
all 8
CHR$( 72)
0
1
0
0
1
0
0
0
#2 & #5
93
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