H838532H datasheet(348/508 Pages) RENESAS

348 / 508 page

Section 10 Serial Communication Interface

Rev. 1.00 May 30, 2008 Page 328 of 484

REJ09B0436-0100

(3) Data Transfer Operations

SCI3 initialization: Data transfer on SCI3 first of all requires that SCI3 be initialized as described

in 10.3.2.3. SCI3 initialization, and shown in figure 10.5.

Transmitting: Figure 10.11 shows an example of a flowchart for data transmission. This

procedure should be followed for data transmission after initializing SCI3.

Start

End

Read bit TDRE

in SSR

Sets bits SPC31 and

SPC32 to 1 in SPCR

Write transmit

data to TDR

Read bit TEND

in SSR

Clear bit TE to 0

in SCR3

TDRE = 1?

Yes

Continue data

transmission?

TEND = 1?

Yes

Read the serial status register (SSR) and

check that bit TDRE is set to 1, then write

transmit data to the transmit data register

(TDR). When data is written to TDR, bit

TDRE is cleared to 0 automatically, the

clock is output, and data transmission is

started. When clock output is selected,

the clock is output and data transmission

started when data is written to TDR.

When continuing data transmission, be

sure to read TDRE = 1 to confirm that

a write can be performed before writing

data to TDR. When data is written to

TDR, bit TDRE is cleared to 0 automatically.

Figure 10.11 Example of Data Transmission Flowchart (Synchronous Mode)

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