MC68LC302 Datasheet, PDF (84/169 Pages) Motorola, Inc – Low Power Integrated Multiprotocol Processor Reference Manual

Communications Processor (CP)
the fact that the sampling rate may not perfectly divide into the
desired UART rate, can make this distinction difficult to achieve
in some scenarios.
4.3.9.5 LOOKUP TABLE EXAMPLE.
Table 4-6 is an example autobaud lookup table. The maximum start and nominal start val-
ues are derived assuming a 1.8432 MHz sampling clock on TIN1 or RCLK and a shift factor
of 5%.
Table 4-6. Lookup Table Example
Desired
Baud Rate
115200
57600
38400
28800
19200
14400
12000
9600
7200
4800
2400
1200
600
300
110
Maximum
Start
17
34
50
67
101
134
161
202
269
403
806
1613
3226
6451
17594
Nominal
Start
8
16
24
32
48
64
77
96
128
192
384
768
1536
3072
8378
4.3.9.6 DETERMINING CHARACTER LENGTH AND PARITY. Table 4-7 shows the dif-
ferent possible character lengths and parity that will be discussed. The following paragraphs
will discuss for each case how to determine the parity.
Table 4-7. Character Lengths and Parity Cases
Case #
1
2
3
4
5
Character
Length
7-bit
7-bit
8-bit
8-bit
8-bit
Parity
No parity, 1 STOP bit
Even parity
Odd parity
Parity=1
Parity=0
No parity
Even parity
Odd parity
Parity=0
Parity=1
Notes
Not Supported
Parity is indicated by the most signif-
icant bit of the byte
Same as 7-bit, parity=0
Parity is indicated by which charac-
ters generate a FE interrupt
Not Supported
• Case 1– This case cannot be supported because the autobaud can not separate the
first character from the second character.
MOTOROLA
MC68LC302 REFERENCE MANUAL
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