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Section 10 Serial Communication Interface
Rev. 6.00 Sep 12, 2006 page 328 of 526
REJ09B0326-0600
Simultaneous Transmit/Receive:
Figure 10.20 shows an example of a flowchart for a
simultaneous transmit/receive operation. This procedure should be followed for simultaneous
transmission/reception after initializing SCI3.
Start
End
Read bit TDRE
in SSR
1
2
3
4
Write transmit
data to TDR
Read bit OER
in SSR
Read bit RDRF
in SSR
Clear bits TE and
RE to 0 in SCR
Yes
TDRE = 1?
No
OER = 1?
No
RDRF = 1?
Yes
Continue data
transmission/reception?
No
Yes
No
Read receive data
in RDR
Yes
Overrun error
processing
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.
Read SSR and check that bit RDRF is set
to 1. If it is, read the receive data in RDR.
When the RDR data is read, bit RDRF is
cleared to 0 automatically.
When continuing data transmission/reception,
finish reading of bit RDRF and RDR before
receiving the MSB (bit 7) of the current frame.
Before transmitting the MSB (bit 7) of the current
frame, also read TDRE = 1 to confirm that a
write can be performed, then write data to TDR.
When data is written to TDR, bit TDRE is cleared
to 0 automatically, and when the data in RDR is
read, bit RDRF is cleared to 0 automatically.
If an overrun error has occurred, read bit OER
in SSR, and after carrying out the necessary
error processing, clear bit OER to 0. Transmission
and reception cannot be resumed if bit OER is
set to 1. See figure 10.18 for details on overrun
error processing.
1.
2.
3.
4.
Figure 10.20 Example of Simultaneous Data Transmission/Reception Flowchart
(Synchronous Mode)
Summary of Contents for F-ZTAT H8/3642A Series
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Page 124: ...Section 5 Power Down Modes Rev 6 00 Sep 12 2006 page 102 of 526 REJ09B0326 0600 ...
Page 188: ...Section 6 ROM Rev 6 00 Sep 12 2006 page 166 of 526 REJ09B0326 0600 ...
Page 190: ...Section 7 RAM Rev 6 00 Sep 12 2006 page 168 of 526 REJ09B0326 0600 ...
Page 298: ...Section 9 Timers Rev 6 00 Sep 12 2006 page 276 of 526 REJ09B0326 0600 ...
Page 378: ...Section 12 A D Converter Rev 6 00 Sep 12 2006 page 356 of 526 REJ09B0326 0600 ...
Page 446: ...Section 13 Electrical Characteristics Rev 6 00 Sep 12 2006 page 424 of 526 REJ09B0326 0600 ...