MC68HC908GR16 Datasheet, PDF (177/310 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Enhanced Serial Communications Interface (ESCI) Module
I/O Registers
NOTE:
M — Mode (Character Length) Bit
This read/write bit determines whether ESCI characters are eight or nine bits
long (See Table 14-5).The ninth bit can serve as a receiver wakeup signal or as
a parity bit. Reset clears the M bit.
1 = 9-bit ESCI characters
0 = 8-bit ESCI characters
Table 14-5. Character Format Selection
Control Bits
M PEN:PTY
0
0X
1
0X
0
10
0
11
1
10
1
11
Start Bits
1
1
1
1
1
1
Character Format
Data Bits Parity Stop Bits
8
None
1
9
None
1
7
Even
1
7
Odd
1
8
Even
1
8
Odd
1
Character Length
10 bits
11 bits
10 bits
10 bits
11 bits
11 bits
WAKE — Wakeup Condition Bit
This read/write bit determines which condition wakes up the ESCI: a logic 1
(address mark) in the MSB 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 ESCI 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 ESCI parity function (see Table 14-5). When
enabled, the parity function inserts a parity bit in the MSB position (see Table
14-3). Reset clears the PEN bit.
1 = Parity function enabled
0 = Parity function disabled
PTY — Parity Bit
This read/write bit determines whether the ESCI generates and checks for odd
parity or even parity (see Table 14-5). 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.
MC68HC908GR16 — Rev. 1.0
MOTOROLA
Enhanced Serial Communications Interface (ESCI) Module
For More Information On This Product,
Go to: www.freescale.com
Data Sheet
177