H8SLASH3021 datasheet(397/712 Pages) RENESAS

397 / 712 page

11. Serial Communication Interface

Rev.2.00 Mar. 22, 2007 Page 373 of 684

REJ09B0352-0200

Transmitting and Receiving Data

Transmitting Multiprocessor Serial Data: Figure 11.10 shows a sample flowchart for

transmitting multiprocessor serial data and indicates the procedure to follow.

Yes

Initialize

Start transmitting

Read TDRE flag in SSR

TDRE = 1?

Write transmit data in

TDR and set MPBT bit in SSR

Clear TDRE flag to 0

All data transmitted?

Read TEND flag in SSR

TEND = 1?

SCI initialization: the transmit data

output function of the TxD pin is

selected automatically.

SCI status check and transmit data

write: read SSR, check that the TDRE

flag is 1, then write transmit

data in TDR. Also set the MPBT flag to

0 or 1 in SSR. Finally, clear the TDRE

flag to 0.

To continue transmitting serial data:

after checking that the TDRE flag is 1,

indicating that data can be written,

write data in TDR, then clear the TDRE

flag to 0.

To output a break signal at the end of

serial transmission: set the DDR bit to

1 and clear the DR bit to 0 (DDR and

DR are I/O port registers), then clear

the TE bit to 0 in SCR.

Output break signal?

Clear DR bit to 0, set DDR bit to 1

Clear TE bit to 0 in SCR

End

Figure 11.10 Sample Flowchart for Transmitting Multiprocessor Serial Data

H8/3021 Datasheet(PDF) 397 Page - Renesas Technology Corp