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❍ Initialization
The appropriate setting values for the control registers when using synchronous mode are
shown below.
[Serial mode register (SMR)]
•
MD1 and MD0: "10"
•
CS2, CS1, CS0: Specify the clock source determined by the clock selector.
•
SCKE: "1" if the dedicated baud rate generator or internal clock is used, "0" when the
external clock is used.
•
SOE: "1" for sending. "0" for only receiving.
[Serial control register (SCR)]
•
PEN: "0"
•
P, SBL, A/D: These bits have no effect.
•
CL: "1" (8-bit data)
•
REC: "0" (Error flag clear for initialization)
•
RXE: TXE: Ensure that at least one of RXE and TXE is "1".
[Serial status Register (SSR)]
•
RIE: "1" when interrupts are used. "0" when no interrupts are used.
•
TIE: "0"
❍ Communication start
Start communication by writing to the serial output register (SODR). Note that temporary data
must be written to the SODR before starting communication, even when receiving data.
❍ Communication end
After the end of transmission and reception of one data frame, the RDRF flag of the serial status
register (SSR) is set to "1". During reception, check the overrun error flag bit (SSR: ORE) and
decide whether communication has been performed normally.
CHAPTER 19 UART
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