MC9S12T64 Datasheet, PDF (437/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
Functional Description
Baud rate generation is subject to two sources of error:
• Integer division of the bus clock may not give the exact target
frequency.
• Synchronization with the bus clock can cause phase shift.
Table 76 lists some examples of achieving target baud rates with a bus
clock frequency of 16 MHz
SCI baud rate = Bus Clock / (16 *SBR[12:0])
Table 76 Baud Rates (Example: Bus Clock = 16.0 MHz)
Bits
SBR[12-0]
13
26
52
104
208
417
833
1664
Receiver
Clock (Hz)
1,230,769
615,385
307,692
153,846
76,923
38,369
19,207
9,598
Transmitter
Clock (Hz)
76923
38,462
19,231
9615
4808
2398
1200
600
Target
Baud Rate
76800
38,400
19,200
9600
4800
2400
1200
600
Error
(%)
0.16
0.16
0.16
0.16
0.16
-0.08
0.04
-0.02
NOTE: The maximum divider rate is 8191.
Serial Communications Interface (SCI)
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MC9S12T64Revision 1.1.1