MC68HC08AS32 Datasheet, PDF (171/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

NOTE:
M — Mode (Character Length) Bit
This read/write bit determines whether SCI characters are eight or nine bits
long. (See Table 12-5.) 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 PTE1/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 can 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 12-5.) When
enabled, the parity function inserts a parity bit in the most significant bit position.
(See Figure 12-4.) 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 12-5.) Reset clears the PTY bit.
1 = Odd parity
0 = Even parity
Changing the PTY bit in the middle of a transmission or reception can generate a
parity error.
Control Bits
M PEN:PTY
0
0X
1
0X
0
10
0
11
1
10
1
11
Table 12-5. Character Format Selection
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
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
171