Datasheet

Table Of Contents
Section 18 Serial Communication Interface 4 (SCI4)
Rev. 2.00 Jul. 04, 2007 Page 424 of 692
REJ09B0309-0200
18.4.4 Data Transmission
Figure 18.4 shows an example flowchart of data transmission. Data transmission should be
performed as the following procedure after the SCI4 initialization.
Read TDRE in SCSR4
TDRE = 1?
Write transmit data in TDR4
TDRE bit cleared to 0 automatically
Data transferred from TDR4 to SR4
Start transmission by setting
TDRE bit to 1
Transmission will
continue?
Read TEND in SCSR4
TEND = 1?
TEI occurs (TEIE = 1)
Clear TE bit in SCR4 to 0
<Transmission completed>
Note: Hatching area indicates SCI internal operation.
Yes
No
Yes
No
Yes
No
[1] Pin SO4 functions as output pin for transmit
data
[2] After reading SCSR4 and confirming TDRE
= 1, write transmit data in TDR4. Writing data
in TDR4 clears the TDRE bit to 0 automati-
cally. At this time, the clock is output to start
data transmission.
[3] To consecutively transmit data, read TDRE
= 1 to confirm that TDR4 is ready. After that,
write data in TDR4. Writing data in TDR4
clears the TDRE bit to 0 automatically.
[1]
[2]
[3]
Initialization
Start transmission (TE = 1)
Figure 18.4 Flowchart Example of Data Transmission