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There are two workarounds for this issue:
n
Enable an SCI pin other than
n
In the next instruction, enable the remaining SCI pins, including the
Following is an example of one way to initialize the SCI:
1.
Ensure that the SCI is in its individual reset state (PCRE = $0).
2.
Configure the control registers (SCR, SCCR) according to the operating mode, but do not
enable transmitter (TE = 0) or receiver (RE = 0).
Note:
It is now possible to set the interrupts enable bits that are used during the operation.
No interrupt occurs yet.
3.
Enable the SCI by setting the PCRE bits according to which signals are used during operation.
4.
If transmit interrupt is not used, write data to the transmitter.
Note:
If transmitter interrupt enable is set, an interrupt is issued and the interrupt handler
should write data into the transmitter. The DMA channel services the SCI transmit
request if it is programmed to service the SCI transmitter.
5.
Enable transmitters (TE = 1) and receiver (RE = 1) according to use.
Operation starts as follows:
n
For an internally-generated clock, the
the SCI is enabled (Step 3 above) for Asynchronous modes. In Synchronous mode, the
signal is active only while transmitting (that is, a gated clock).
SCLK
n
Data is received only when the receiver is enabled (RE = 1) and after the occurrence of
the SCI receive sequence on the
idle line sequence).
n
Data is transmitted only after the transmitter is enabled (TE = 1), and after the
initialization sequence has been transmitted (depending on the operating mode).
8.4.1
Preamble, Break, and Data Transmission Priority
Two or three transmission commands can be set simultaneously:
n
A preamble (TE is set.)
n
A break (SBK is set or is cleared.)
n
An indication that there is data for transmission (TDRE is cleared.)
After the current character transmission, if two or more of these commands are set, the
transmitter executes them in the following order: preamble, break, data.
.
SCLK
signal starts operation immediately after
SCLK
signal, as defined by the operating mode (that is,
RXD
Serial Communication Interface (SCI)
SCI Initialization
pin.
SCLK
8-7
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