68HC05PD6 Datasheet, PDF (116/165 Pages) Motorola, Inc – SPECIFICATION (General Release)

GENERAL RELEASE SPECIFICATION
July 7, 1997
NOTE
The divided frequencies shown in Table 11-1 represent baud rates
which are the highest transmit baud rate (Tx) that can be obtained
by a specific clock frequency and only using the prescaler division.
Lower baud rate may be obtained by providing a further division
using the SCI rate select bits as shown below for some
representative prescaler outputs
Table 11-2. Transmit Baud Rate Output For a Given Prescaler Output
SCR2 SCR1 SCR0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
DIVIDED
BY
1
2
4
8
16
32
64
128
REPRESENTATIVE HIGHEST PRESCALER BAUD RATE OUPUT
125.000 KHz 39.06 KHz
15.625 KHz
9.600 KHz
125.000 KHz
39.06 KHz
15.625 KHz
9600 Hz
62.5 KHz
19.53 KHz
7.813 KHz
4800 Hz
31.250 KHz
9.765 KHz
3.906 KHz
2400 Hz
15.625 KHz
4.883 KHz
1.953 KHz
1200 Hz
7.813 KHz
2.441 KHz
977 Hz
600 Hz
3.906 KHz
1.221 KHz
488 Hz
300 Hz
1.953 KHz
610 Hz
244 Hz
150 Hz
977 Hz
305 Hz
122 Hz
75 Hz
NOTE
Table 11-2 illustrates how the SCI select bits can be used to provide
lower transmitter baud rates by further dividing the prescaler output
frequency. The four examples are only representative samples. In all
cases, the baud rates shown are transmit baud rates (transmit clock)
and the receiver clock is 16 times higher in frequency than the
actual baud rate.
MOTOROLA
11-14
SERIAL COMMUNICATIONS INTERFACE
MC68HC05PD6
REV 1.1