MC68HC705C9A_1 Datasheet, PDF (82/157 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
General Release Specification _{SCI Receiver Features}
9.4 SCI Receiver Features
Features of the SCI receiver include:
• Receiver Wakeup Function (Idle Line or Address Bit)
• Idle Line Detection
• Framing Error Detection
• Noise Detection
• Overrun Detection
• Receiver Data Register Full Flag
9.5 SCI Transmitter Features
Features of the SCI transmitter include:
• Transmit Data Register Empty Flag
• Transmit Complete Flag
• Send Break
9.6 Functional Description
A block diagram of the SCI is shown in Figure 9-1. Option bits in serial
control register1 (SCCR1) select the wakeup method (WAKE bit) and
data word length (M bit) of the SCI. SCCR2 provides control bits that
individually enable the transmitter and receiver, enable system
interrupts, and provide the wakeup enable bit (RWU) and the send break
code bit (SBK). Control bits in the baud rate register (BAUD) allow the
user to select one of 32 different baud rates for the transmitter and
receiver.
Data transmission is initiated by writing to the serial communications
data register (SCDR). Provided the transmitter is enabled, data stored in
the SCDR is transferred to the transmit data shift register. This transfer
of data sets the transmit data register empty flag (TDRE) in the SCI
status register (SCSR) and generates an interrupt (if transmitter
MC68HC705C9A — Rev. 2.0
Serial Communications Interface (SCI)
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