PXN20RM Datasheet, PDF (1013/1376 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Enhanced Serial Communication Interface (eSCI)
START
BIT BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8
START
BIT BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9
START
BIT BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10 BIT11
START
BIT BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10 BIT11 BIT12
Figure 31-21. SCI Break Character Formats
31.4.2.3 Idle Character Formats
An idle character is a sequence of bits with the value 1. The supported idle character formats are specified
in Table 31-18. The preamble has the same structure and content as an idle character.
Table 31-18. Supported Idle Character Formats
Control
Idle Character Length
eSCI_CR3[M2] eSCI_CR1[M]
SCI Idle Characters (see Figure 31-22)
0
0
10
0
1
11
1
0
12
1
1
16
The structure and content of the SCI idle characters is shown in Figure 31-22.
BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9
BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10
BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10 BIT11
BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10 BIT11 BIT12 BIT13 BIT14 BIT14
Figure 31-22. SCI Idle Character Formats
31.4.3 Baud Rate and Clock Generation
A 13-bit modulus counter in the baud rate generator derives the baud rate for both the receiver and the
transmitter. The value written to the SBR field in the eSCI Baud Rate Register (eSCI_BRR) determines
the module 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 has an acquisition rate of 16 samples
per bit time.
Freescale Semiconductor
PXN20 Microcontroller Reference Manual, Rev. 1
31-23