MC908JL8CDWE Datasheet, PDF (135/212 Pages) Freescale Semiconductor, Inc – Microcontrollers

I/O Registers
M — Mode (Character Length) Bit
This read/write bit determines whether SCI characters are eight or nine bits long. (See Table 9-5.) The
ninth bit can serve as an extra stop bit, as a receiver wakeup signal, or as a parity bit. Reset clears the
M bit.
1 = 9-bit SCI characters
0 = 8-bit SCI characters
WAKE — Wakeup Condition Bit
This read/write bit determines which condition wakes up the SCI: a logic 1 (address mark) in the most
significant bit position of a received character or an idle condition on the RxD pin. Reset clears the
WAKE bit.
1 = Address mark wakeup
0 = Idle line wakeup
ILTY — Idle Line Type Bit
This read/write bit determines when the SCI starts counting logic 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 logic 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 9-5.) When enabled, the parity function
inserts a parity bit in the most significant bit position. (See Figure 9-3.) 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 9-5.) 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 9-5. Character Format Selection
Control Bits
M
PEN and PTY
0
0X
1
0X
0
10
0
11
1
10
1
11
Start
Bits
1
1
1
1
1
1
Data
Bits
8
9
7
7
8
8
Character Format
Parity
Stop
Bits
None
1
None
1
Even
1
Odd
1
Even
1
Odd
1
Character
Length
10 bits
11 bits
10 bits
10 bits
11 bits
11 bits
MC68HC908JL8/JK8 • MC68HC08JL8/JK8 • MC68HC908KL8 Data Sheet, Rev. 3.1
Freescale Semiconductor
135