Figure 19.4 Sample Flowchart For Transmitting Serial Data - Renesas HD6417641 Hardware Manual

• Transmitting Serial Data (Asynchronous Mode)
Figure 19.4 shows a sample flowchart for serial transmission.
Use the following procedure for serial data transmission after enabling the SCIF for transmission.
Start of transmission
Read TDFE flag in SCFSR
Write transmit data in SCFTDR,
and read 1 from TDFE flag
and TEND flag in SCFSR,
then clear to 0
All data transmitted?
Read TEND flag in SCFSR
Break output?
Clear SPB2DT to 0 and
set SPB2IO to 1
Clear TE bit in SCSCR to 0
End of transmission

Figure 19.4 Sample Flowchart for Transmitting Serial Data

No
TDFE = 1?
Yes
No
Yes
No
TEND = 1?
Yes
No
Yes
Section 19 Serial Communication Interface with FIFO (SCIF)
[1] SCIF status check and transmit data
write:
Read SCFSR and check that the
TDFE flag is set to 1, then write
transmit data to SCFTDR, and read 1
from the TDFE and TEND flags, then
clear to 0.
The number of transmit data bytes
that can be written is 16 - (transmit
[1]
trigger set number).
[2] Serial transmission continuation
procedure:
To continue serial transmission, read
[2]
1 from the TDFE flag to confirm that
writing is possible, then write data to
SCFTDR, and then clear the TDFE
flag to 0.
[3] Break output at the end of serial
transmission:
To output a break in serial
transmission, clear the SPB2DT bit to
0 and set the SPB2IO bit to 1 in
SCSPTR, then clear the TE bit in
SCSCR to 0.
In [1] and [2], it is possible to
ascertain the number of data bytes
that can be written from the number
of transmit data bytes in SCFTDR
[3]
indicated by the upper 8 bits of
SCFDR.
Rev. 4.00 Sep. 14, 2005 Page 727 of 982
REJ09B0023-0400