MC68HC711G5 MOTOROLA [Motorola, Inc], MC68HC711G5 Datasheet - Page 98

• Manufacturer Part Number: MC68HC711G5
• Description: High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller
• Manufacturer: MOTOROLA [Motorola, Inc]

Transmit data is the serial data from the internal data bus that is applied through the serial
communications interface to the output line. The transmitter generates a bit time by using a
derivative of the RT clock, thus producing a transmission rate equal to 1/16th that of the receiver
sample clock.
Primarily the SCI system is configured and controlled by five registers BAUD, SCCR1, SCCR2,
SCSR, and SCDAT). In addition, the Port D data and data direction registers and the Port D wired-
OR mode bit in the SPCR register are secondarily related to the SCI system. Reference should be
made to the block diagram shown in Figure 7-1.
7.8.1
The SCI data register (SCDAT) shown in the following figure is actually two separate registers.
When SCDAT is read, the read-only receive data register is accessed and when SCDAT is written,
the write-only transmit data register is accessed.
READ:
WRITE:
RESET:
7.8.2
The SCI control register 1 (SCCR1) contains control bits related to the nine data bit character format
and the receiver wake-up feature. Four of the bits in this register are not used and always read as
zeros.
MOTOROLA
7-8
7.7
7.8
TRANSMIT DATA (TXD)
SCI REGISTERS
Serial Communications Data Register (SCDAT)
Serial Communications Control Register 1 (SCCR1)
RESET:
RESET:
Accesses the read-only SCI receive data register (RDR).
Accesses the write-only SCI transmit data register (TDR).
Does not affect this address.
$102F
$102C
BIT7
R8
U
7
0
7
BIT6
T8
U
6
0
6
SERIAL COMMUNICATIONS INTERFACE
BIT5
5
0
5
0
0
BIT4
M
4
0
4
0
WAKE
BIT3
3
0
3
0
BIT2
2
0
2
0
0
BIT1
1
0
1
0
0
BIT0
0
0
0
0
0
SCDAT
SCCR1
MC68HC11G5