
Enhanced Serial Communication Interface (eSCI)
MPC5566 Microcontroller Reference Manual, Rev. 2
21-20
Freescale Semiconductor
21.4.3
Baud Rate Generation
A 13-bit modulus counter in the baud rate generator derives the baud rate for both the receiver and the
transmitter. The value, 1 to 8191, written to the SBR0–SBR12 bits determines the system clock divider.
The SBR bits are in the eSCI control register 1 (ESCI
x
_CR1). The baud rate clock is synchronized with
the system clock and drives the receiver. The baud rate clock divided by 16 drives the transmitter. The
receiver has an acquisition rate of 16 samples per bit time.
Baud rate generation is subject to one source of error when integer division of the system clock does not
result in the exact target frequency.
lists some examples of achieving target baud rates with a system clock frequency of 128 MHz.
Table 21-17. Baud Rates (Example: System Clock = 128 MHz)
Bits
SBR[0:12]
Receiver
Clock (Hz)
Transmitter
Clock (Hz)
Target Baud
Rate
Error
(%)
0x0023
3,657,143
228,571
230,400
–0.79
0x0045
1,855,072
115,942
115,200
+0.64
0x008B
920,863
57,554
57,600
–0.01
0x00D0
615,385
38,462
38,400
+0.16
0x01A1
306,954
19,185
19,200
–0.08
0x022C
230,216
14,388
14,400
–0.08
0x0341
153,661
9,604
9600
+.04
0x0683
76,785
4,799
4800
–0.02
0x0D05
38,404
2,400.2
2400
+.01
0x1A0A
19,202
1,200.1
1200
+.01
SCI baud rate
System clock
16
ESCIx_CR1[SBR]
×
-------------------------------------------------------------
=
Содержание MPC5566
Страница 12: ...MPC5566 Microcontroller Reference Manual Devices Supported MPC5566 MPC5566 RM Rev 2 0 23 Apr 2008...
Страница 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Страница 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Страница 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Страница 331: ...System Integration Unit SIU MPC5566 Microcontroller Reference Manual Rev 2 6 128 Freescale Semiconductor...
Страница 343: ...Crossbar Switch XBAR MPC5566 Microcontroller Reference Manual Rev 2 7 12 Freescale Semiconductor...
Страница 361: ...Error Correction Status Module ECSM MPC5566 Microcontroller Reference Manual Rev 2 8 18 Freescale Semiconductor...
Страница 455: ...Interrupt Controller INTC MPC5566 Microcontroller Reference Manual Rev 2 10 42 Freescale Semiconductor...
Страница 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Страница 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Страница 679: ...Boot Assist Module BAM MPC5566 Microcontroller Reference Manual Rev 2 16 20 Freescale Semiconductor...
Страница 997: ...Deserial Serial Peripheral Interface DSPI MPC5566 Microcontroller Reference Manual Rev 2 20 72 Freescale Semiconductor...
Страница 1037: ...Enhanced Serial Communication Interface eSCI MPC5566 Microcontroller Reference Manual Rev 2 21 40 Freescale Semiconductor...
Страница 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Страница 1081: ...Voltage Regulator Controller VRC and POR Module MPC5566 Microcontroller Reference Manual Rev 2 23 8 Freescale Semiconductor...
Страница 1093: ...IEEE 1149 1 Test Access Port Controller JTAGC MPC5566 Microcontroller Reference Manual Rev 2 24 12 Freescale Semiconductor...
Страница 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...
Страница 1267: ...MPC5566 Reference Manual Revision History MPC5566 Microcontroller Reference Manual Rev 2 Freescale Semiconductor C 10...
Страница 1268: ...MPC5566 Reference Manual Revision History MPC5566 Microcontroller Reference Manual Rev 2 Freescale Semiconductor C 11...