mc9s08sg4 Freescale Semiconductor, Inc, mc9s08sg4 Datasheet - Page 209

• Manufacturer Part Number: mc9s08sg4
• Description: 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

1
14.2.7
This register is actually two separate registers. Reads return the contents of the read-only receive data
buffer and writes go to the write-only transmit data buffer. Reads and writes of this register are also
involved in the automatic flag clearing mechanisms for the SCI status flags.
14.3
The SCI allows full-duplex, asynchronous, NRZ serial communication among the MCU and remote
devices, including other MCUs. The SCI comprises a baud rate generator, transmitter, and receiver block.
The transmitter and receiver operate independently, although they use the same baud rate generator. During
normal operation, the MCU monitors the status of the SCI, writes the data to be transmitted, and processes
received data. The following describes each of the blocks of the SCI.
14.3.1
As shown in
Freescale Semiconductor
Setting TXINV inverts the TxD output for all cases: data bits, start and stop bits, break, and idle.
Reset
TXINV
Field
ORIE
NEIE
FEIE
PEIE
4
3
2
1
0
W
R
1
Functional Description
SCI Data Register (SCID)
Baud Rate Generation
Transmit Data Inversion — Setting this bit reverses the polarity of the transmitted data output.
0 Transmit data not inverted
1 Transmit data inverted
Overrun Interrupt Enable — This bit enables the overrun flag (OR) to generate hardware interrupt requests.
0 OR interrupts disabled (use polling).
1 Hardware interrupt requested when OR = 1.
Noise Error Interrupt Enable — This bit enables the noise flag (NF) to generate hardware interrupt requests.
0 NF interrupts disabled (use polling).
1 Hardware interrupt requested when NF = 1.
Framing Error Interrupt Enable — This bit enables the framing error flag (FE) to generate hardware interrupt
requests.
0 FE interrupts disabled (use polling).
1 Hardware interrupt requested when FE = 1.
Parity Error Interrupt Enable — This bit enables the parity error flag (PF) to generate hardware interrupt
requests.
0 PF interrupts disabled (use polling).
1 Hardware interrupt requested when PF = 1.
R7
T7
Figure
0
7
14-12, the clock source for the SCI baud rate generator is the bus-rate clock.
R6
T6
0
6
Table 14-7. SCIC3 Field Descriptions (continued)
MC9S08SG8 MCU Series Data Sheet, Rev. 3
Figure 14-11. SCI Data Register (SCID)
R5
T5
0
5
R4
T4
0
4
Description
Chapter 14 Serial Communications Interface (S08SCIV4)
R3
T3
3
0
R2
T2
0
2
R1
T1
0
1
R0
T0
0
0
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