Chapter 12 Serial Communication Interface (S12SCIV6)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
494
Freescale Semiconductor
12.4.3
Data Format
The SCI uses the standard NRZ mark/space data format. When Infrared is enabled, the SCI uses RZI data
format where zeroes are represented by light pulses and ones remain low. See
Figure 12-15. SCI Data Formats
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 SCI control register 1 configures the SCI for 8-bit data characters. A frame with eight
data bits has a total of 10 bits. Setting the M bit configures the SCI for nine-bit data characters. A frame
with nine data bits has a total of 11 bits.
When the SCI is configured for 9-bit data characters, the ninth data bit is the T8 bit in SCI data register
high (SCIDRH). 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.
Table 12-14. Example of 8-Bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
1
8
0
0
1
1
7
0
1
1
1
7
1
(1)
1. The address bit identifies the frame as an address
character. See
Section 12.4.6.6, “Receiver Wakeup”
.
0
1
Table 12-15. Example of 9-Bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
1
9
0
0
1
1
8
0
1
1
1
8
1
(1)
0
1
Bit 5
Start
Bit
Bit 0
Bit 1
Next
STOP
Bit
Start
Bit
8-Bit Data Format
(Bit M in SCICR1 Clear)
Start
Bit
Bit 0
NEXT
STOP
Bit
START
Bit
9-Bit Data Format
(Bit M in SCICR1 Set)
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 8
Bit 2
Bit 3
Bit 4
Bit 6
Bit 7
POSSIBLE
PARITY
Bit
Possible
Parity
Bit
Standard
SCI Data
Infrared
SCI Data
Standard
SCI Data
Infrared
SCI Data
