MC68HC711xxxx Motorola, MC68HC711xxxx Datasheet - Page 122

• Manufacturer Part Number: MC68HC711xxxx
• Description: Microcontrollers
• Manufacturer: Motorola

Serial Communications Interface (SCI)
7.7 SCI Registers
7.7.1 Serial Communications Data Register
Data Sheet
122
Five addressable registers are associated with the SCI:
The SCI registers are the same for all M68HC11 E-series devices with one
exception. The SCI system for MC68HC(7)11E20 contains an extra bit in the
BAUD register that provides a greater selection of baud prescaler rates. Refer to
7.7.5 Baud Rate
SCDR is a parallel register that performs two functions:
Reads access the receive data buffer and writes access the transmit data buffer.
Receive and transmit are double buffered.
•
•
•
•
Address:
Reset:
Read:
Write:
Four control and status registers:
–
–
–
–
One data register:
–
The receive data register when it is read
The transmit data register when it is written
Figure 7-3. Serial Communications Data Register (SCDR)
Serial communications control register 1 (SCCR1)
Serial communications control register 2 (SCCR2)
Baud rate register (BAUD)
Serial communications status register (SCSR)
Serial communications data register (SCDR)
$102F
R7/T7
Bit 7
Serial Communications Interface (SCI)
Register,
R6/T6
6
Figure
R5/T5
5
7-8, and
Indeterminate after reset
R4/T4
4
Figure
R3/T3
3
7-9.
R2/T2
M68HC11E Family — Rev. 5
2
R1/T1
1
MOTOROLA
R0/T0
Bit 0