Radio Shack TRS-80 Model III - Page 56

TRS-80
MODEL
III
In
technical
terms
,
we are storing
the send-rate
code in the most
significant four bits
(
'
'nibble
"
)
of
1
6888
,
and the
receive-code
in the least significant
nibble
.
Baud-Rate
Codes
Desired
Error
Baud Rate
Baud Rate
(%)
Code
50
75
1
110
2
134.5
0.016
3
150
4
300
5
600
6
1200
7
1800
8
2000 0.253
9
2400
10
3600
11
4800
12
7200
13
9600
14
19200
3.125
15
Parity/Word
Length/Stop-Bit
Code
You
pack
all of this
information
into
one
byte, using
the following
formula:
Code
where:
(Parityselect
*
128)
+ (Word
*
32)
+
(Stop
*
16)
+
(Parityonoff*
8)
+ (Transmit *4)
+
(DTR
*2) +
RTS
Parityselect =
for
odd parity
=
1 for
even
parity
Word
=
for
5-bit
words
=
1
for
6-bit
words
=
2
for
7-bit
words
=
3
for
8-bit words
Stop
=
for
1 stop-bit
=
1
for
2 stop-bit
Parityonoff =
to enable
parity
=
1
to
disable parity
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