Specifications

SCI Programmable Data Format
8-8
8.2 SCI Programmable Data Format
SCI data, both receive and transmit, is in NRZ (nonreturn-to-zero) format. The
NRZ data format, shown in Figure 8–2, consists of:
- one start bit
- one to eight data bits
- an even/odd parity bit (optional)
- one or two stop bits
- an extra bit to distinguish addresses from data (address-bit mode only)
The basic unit of data is called a character and is one to eight bits in length.
Each character of data is formatted with a start bit, one or two stop bits, and
optional parity and address bits. A character of data with its formatting informa-
tion is called a frame and is shown in Figure 8–2.
Figure 8–2. Typical SCI Data Frame Formats
Start LSB 2 3 Parity Stop4567MSB
Start LSB 2 3
Addr/
data
Parity
4 5 6 7 MSB Stop
Idle-line mode
(Normal nonmultiprocessor communications)
Address-bit mode
Address bit
To program the data format, use the SCICCR register. The bits used to pro-
gram the data format are shown in Table 8–2.
Table 8–2. Programming the Data Format Using SCICCR
Bit Name Designation Functions
SCI CHAR2–0 SCICCR.2–0 Select the character (data) length (one to
eight bits). Bit values are shown in
Table 8–4 (page 8-21).
PARITY ENABLE SCICCR.5 Enables the parity function if set to 1, or
disables the parity function if cleared to 0.
EVEN/ODD PARITY SCICCR.6 If parity is enabled, selects odd parity if
cleared to 0 or even parity if set to 1.
STOP BITS SCICCR.7 Determines the number of stop bits trans-
mitted—one stop bit if cleared to 0 or two
stop bits if set to 1.