MC68HC705C9A_1 Datasheet, PDF (84/157 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
General Release Specification _{Data Format}
9.7 Data Format
Receive data or transmit data is the serial data that is transferred to the
internal data bus from the receive data input pin (RDI) or from the
internal bus to the transmit data output pin (TDO). The
non-return-to-zero (NRZ) data format shown in Figure 9-3 is used and
must meet the following criteria:
• The idle line is brought to a logic one state prior to
transmission/reception of a character.
• A start bit (logic zero) is used to indicate the start of a frame.
• The data is transmitted and received least significant bit first.
• A stop bit (logic one) is used to indicate the end of a frame. A
frame consists of a start bit, a character of eight or nine data bits,
and a stop bit.
• A break is defined as the transmission or reception of a low (logic
zero) for at least one complete frame time.
IDLE LINE
CONTROL BIT M SELECTS
8- OR 9-BIT DATA
012345678
0
START
Figure 9-3. Data Format
STOP START
MC68HC705C9A — Rev. 2.0
Serial Communications Interface (SCI)
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