Section 14 Serial Communication Interface (SCI)
Rev. 5.00 May 29, 2006 page 413 of 698
REJ09B0146-0500
In transmitting serial data, the SCI operates as follows:
1. The SCI monitors the TDRE bit in the SCSSR. When TDRE is cleared to 0 the SCI recognizes
that the SCTDR contains new data and loads this data from the SCTDR into the SCTSR.
2. After loading the data from the SCTDR into the SCTSR, the SCI sets the TDRE bit to 1 and
starts transmitting. If the transmit-data-empty interrupt enable bit (TIE) in the SCSCR is set to
1, the SCI requests a transmit-data-empty interrupt (TXI) at this time.
If clock output mode is selected, the SCI outputs eight synchronous clock pulses. If an external
clock source is selected, the SCI outputs data in synchronization with the input clock. Data are
output from the TxD0 pin in order from the LSB (bit 0) to the MSB (bit 7).
3. The SCI checks the TDRE bit when it outputs the MSB (bit 7). If TDRE is 0, the SCI loads
data from the SCTDR into the SCTSR, then begins serial transmission of the next frame. If
TDRE is 1, the SCI sets the TEND bit in the SCSSR to 1, transmits the MSB, then holds the
transmit data pin (TxD0) in the MSB state. If the TEIE in the SCSCR is set to 1, a transmit-end
interrupt (TEI) is requested at this time.
4. After the end of serial transmission, the SCK0 pin is held in the high state.
Figure 14.20 shows an example of SCI transmit operation.
Bit 0
Bit 1
Bit 7
Bit 0
Bit 1
Bit 6
Synchronization
clock
Serial data
Transfer direction
Bit 7
Writes data to TDR
with the TXI interrupt
processing routine
and clears TDRE
bit to 0
1 frame
TDRE
TEND
LSB
MSB
TXI interrupt
request
generated
TXI interrupt
request
generated
TEI interrupt
request
generated
Figure 14.20 Example of SCI Transmit Operation
Summary of Contents for SH7706 Series
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Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...