MC68908GZ8MFJE Datasheet, PDF (197/314 Pages) Freescale Semiconductor, Inc – Microcontrollers

I/O Registers
TXINV — Transmit Inversion Bit
This read/write bit reverses the polarity of transmitted data. Reset clears the TXINV bit.
1 = Transmitter output inverted
0 = Transmitter output not inverted
NOTE
Setting the TXINV bit inverts all transmitted values including idle, break,
start, and stop bits.
M — Mode (Character Length) Bit
This read/write bit determines whether ESCI characters are eight or nine bits long (See
Table 15-5).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 15-5. 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 15-5). When enabled, the parity function
inserts a parity bit in the MSB position (see
Table 15-3). Reset clears the PEN bit.
1 = Parity function enabled
0 = Parity function disabled
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Freescale Semiconductor
197