SH7052 datasheet(512/919 Pages) RENESAS

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Transmitting and Receiving Data

SCI Initialization (Synchronous Mode): Before transmitting or receiving, software must clear

the TE and RE bits to 0 in the serial control register (SCR), then initialize the SCI as follows.

When changing the mode or communication format, always clear the TE and RE bits to 0 before

following the procedure given below. Clearing TE to 0 sets TDRE to 1 and initializes the transmit

shift register (TSR). Clearing RE to 0, however, does not initialize the RDRF, PER, FER, and

ORER flags and receive data register (RDR), which retain their previous contents.

Figure 14.18 is a sample flowchart for initializing the SCI.

1. Select the clock source in the serial control register (SCR). Leave RIE, TIE, TEIE, MPIE, TE,

and RE cleared to 0.

2. Select the communication format in the serial mode register (SMR) and serial direction control

3. Write the value corresponding to the bit rate in the bit rate register (BRR) (unless an external

clock is used).

4. Wait for at least the interval required to transmit or receive one bit, then set TE or RE in the

serial control register (SCR) to 1.* Also set RIE, TIE, TEIE, and MPIE. The TxD, RxD pins

becomes usable in response to the PFC corresponding bits and the TE, RE bit settings.

Note: * In simultaneous transmit/receive operation, the TE bit and RE bit must be cleared to 0 or

set to 1 simultaneously.

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