NXP Semiconductors MPC5566 - Data Format

Enhanced Serial Communication Interface (eSCI)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 21-19
21.4.2 Data Format
The eSCI uses the standard NRZ mark/space data format. Each data character is contained in a frame that
includes a start bit, eight or nine data bits, and a stop bit. Clearing the M bit in eSCI control register 1
configures the eSCI for 8-bit data characters. A frame with eight data bits has a total of 10 bits. Setting the
M bit configures the eSCI for 9-bit data characters. A frame with nine data bits has a total of 11 bits.
When the eSCI is configured for 9-bit data characters, the ninth data bit is the T8 bit in the eSCI data
register (ESCIx_DR). It remains unchanged after transmission and can be used repeatedly without
rewriting it. A frame with nine data bits has a total of 11 bits.
The two different data formats are illustrated in Figure 21-12. Table 21-15 and Table 21-16 show the
number of each type of bit in 8-bit data format and 9-bit data format, respectively.
Figure 21-12. eSCI Data Formats
Table 21-15. Example of 8-bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
18001
17011
17 1
1
1
The address bit identifies the frame as an address
character. Refer to Section 21.4.5.6, “Receiver Wake-up.”
01
Table 21-16. Example of 9-Bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
19001
18011
18 1
1
1
The address bit identifies the frame as an address
character. Refer to Section 21.4.5.6, “Receiver Wake-up.”
01
Parity or
STOP
Bit
Bit 0 Bit 1Bit 2Bit 3Bit 4Bit 5Bit 6Bit 7
Next
START
Bit
START
Bit
Data Bit
8-bit Data Format
Bit M in ESCIx_CR1 Clear
STOP
Bit
Bit 0 Bit 1Bit 2Bit 3Bit 4Bit 5Bit 6Bit 7
Next
START
Bit
START
Bit
9-bit Data Format
Bit M in ESCIx_CR1 Set
Parity or
Bit 8
Data Bit