MC9S12KG128 Datasheet, PDF (337/600 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 10 Serial Communications Interface (SCIV1)
10.4.1 Data Format
The SCI uses the standard NRZ mark/space data format illustrated in Figure 10-10 below.
8-BIT DATA FORMAT
PARITY
START
BIT M IN SCICR1 CLEAR
OR DATA
BIT
NEXT
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 STOP BIT
BIT
9-BIT DATA FORMAT
PARITY
BIT M IN SCICR1 SET
OR DATA
BIT
NEXT
START
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT 8 STOP BIT
BIT
Figure 10-10. 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
Table 10-8. 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
1¹
0
1
1 _{The address bit identifies the frame as an address character. See}
Section 10.4.4.6, “Receiver Wakeup”.
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 10-9. 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
1¹
0
1
1 _{The address bit identifies the frame as an address character. See}
Section 10.4.4.6, “Receiver Wakeup”.
MC9S12KG128 Data Sheet, Rev. 1.15
Freescale Semiconductor
337