Serial Communications Interface Module (SCI)
ILTY — Idle Line Type Bit
This read/write bit determines when the SCI starts counting 1s as idle character
bits. The counting begins either after the start bit or after the stop bit. If the count
begins after the start bit, then a string of 1s preceding the stop bit may cause
false recognition of an idle character. Beginning the count after the stop bit
avoids false idle character recognition, but requires properly synchronized
transmissions. Reset clears the ILTY bit.
1 = Idle character bit count begins after stop bit.
0 = Idle character bit count begins after start bit.
PEN — Parity Enable Bit
This read/write bit enables the SCI parity function. See Table 13-4. When
enabled, the parity function inserts a parity bit in the most significant bit position.
See Figure 13-4. Reset clears the PEN bit.
1 = Parity function enabled
0 = Parity function disabled
PTY — Parity Bit
This read/write bit determines whether the SCI generates and checks for odd
parity or even parity. See Table 13-4. Reset clears the PTY bit.
1 = Odd parity
0 = Even parity
NOTE:
Changing the PTY bit in the middle of a transmission or reception can generate a
parity error.
Table 13-4. Character Format Selection
Control Bits
PEN:PTY
Character Format
Start
Bits
Data
Bits
Stop
Character
Length
M
Parity
Bits
0
1
0
0
1
1
0X
0X
10
11
10
11
1
1
1
1
1
1
8
9
7
7
8
8
None
None
Even
Odd
1
10 bits
11 bits
10 bits
10 bits
11 bits
11 bits
1
1
1
Even
Odd
1
1
Data Sheet
184
MC68HC908MR32 • MC68HC908MR16 — Rev. 6.0
Serial Communications Interface Module (SCI) MOTOROLA
FREESCALE [ Freescale ]
