MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 375

• Manufacturer Part Number: MMC2114
• Description: M CORE Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

17.10 Baud Rate Generation
MMC2114 • MMC2113 • MMC2112 — Rev. 1.0
MOTOROLA
Serial Communications Interface Modules (SCI1 and SCI2)
A 13-bit modulus counter in the baud rate generator derives the baud
rate for both the receiver and the transmitter. The value from 0 to 8191
written to SCIBDH and SCIBDL determines the system clock divisor.
The baud rate clock is synchronized with the bus clock and drives the
receiver. The baud rate clock divided by 16 drives the transmitter. The
receiver acquisition rate is 16 samples per bit time.
Baud rate generation is subject to two sources of error:
SBR[12:0]
1. Integer division of the module clock may not give the exact target
2. Synchronization with the bus clock can cause phase shift.
0x0008f
Freescale Semiconductor, Inc.
0x0012
0x0024
0x0036
0x003d
0x0048
0x006b
0x00d7
0x01ae
0x035b
0x06b7
0x0d6d
0x1adb
For More Information On This Product,
frequency.
Go to: www.freescale.com
Receiver Clock
1,833,333.3
916,666.7
540,983.6
458,333.3
230,769.2
153,488.4
308,411.2
611,111.1
76,744.2
38,416.8
19,197.2
(Hz)
9,601.4
4,800.0
Table 17-4. Example Baud Rates
Serial Communications Interface Modules (SCI1 and SCI2)
(System Clock = 33 MHz)
Transmitter Clock
114,583.3
57,291.7
38,194.4
28,645.8
19,275.7
14,423.1
33,811.4
(Hz)
95,93.0
4,796.5
2,401.0
1,199.8
600.1
300.0
Baud Rate
115,200
Target
Baud Rate Generation
57,600
38,400
33,600
28,800
19,200
14,400
9,600
4,800
2,400
1,200
Advance Information
600
300
Percent
Error
0.54
0.54
0.54
0.63
0.54
0.39
0.16
0.07
0.07
0.04
0.01
0.01
0
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