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Section 13 Serial Communication Interface (SCI)
Rev.2.00 Jun. 28, 2007 Page 520 of 666
REJ09B0311-0200
13.9.5
Relation between Writing to TDR and TDRE Flag
The TDRE flag in SSR is a status flag which indicates that transmit data has been transferred from
TDR to TSR. When the SCI transfers data from TDR to TSR, the TDRE flag is set to 1.
Data can be written to TDR irrespective of the TDRE flag status. However, if new data is written
to TDR when the TDRE flag is 0, that is, when the previous data has not been transferred to TSR
yet, the previous data in TDR is lost. Be sure to write transmit data to TDR after verifying that the
TDRE flag is set to 1.
13.9.6
Restrictions on Using DTC
•
When the external clock source is used as a synchronization clock, update TDR by the DTC
and wait for at least five P
φ
clock cycles before allowing the transmit clock to be input. If the
transmit clock is input within four clock cycles after TDR modification, the SCI may
malfunction (figure 13.33).
•
When using the DTC to read RDR, be sure to set the receive end interrupt (RXI) as the DTC
activation source.
t
D0
LSB
Serial data
SCK
D1
D3
D4
D5
D2
D6
D7
Note: When external clock is supplied, t must be more than four clock cycles.
TDRE
Figure 13.33 Sample Transmission using DTC in Clocked Synchronous Mode
Содержание H8SX/1650
Страница 2: ...Rev 2 00 Jun 28 2007 Page ii of xxii...
Страница 106: ...Section 4 Exception Handling Rev 2 00 Jun 28 2007 Page 84 of 666 REJ09B0311 0200...
Страница 142: ...Section 5 Interrupt Controller Rev 2 00 Jun 28 2007 Page 120 of 666 REJ09B0311 0200...
Страница 326: ...Section 8 I O Ports Rev 2 00 Jun 28 2007 Page 304 of 666 REJ09B0311 0200...
Страница 470: ...Section 12 Watchdog Timer WDT Rev 2 00 Jun 28 2007 Page 448 of 666 REJ09B0311 0200...
Страница 546: ...Section 13 Serial Communication Interface SCI Rev 2 00 Jun 28 2007 Page 524 of 666 REJ09B0311 0200...
Страница 566: ...Section 14 A D Converter Rev 2 00 Jun 28 2007 Page 544 of 666 REJ09B0311 0200...
Страница 574: ...Section 16 RAM Rev 2 00 Jun 28 2007 Page 552 of 666 REJ09B0311 0200...
Страница 584: ...Section 17 Clock Pulse Generator Rev 2 00 Jun 28 2007 Page 562 of 666 REJ09B0311 0200...
Страница 638: ...Section 19 List of Registers Rev 2 00 Jun 28 2007 Page 616 of 666 REJ09B0311 0200...
Страница 668: ...Section 20 Electrical Characteristics Rev 2 00 Jun 28 2007 Page 646 of 666 REJ09B0311 0200...
Страница 676: ...Appendix Rev 2 00 Jun 28 2007 Page 654 of 666 REJ09B0311 0200...
Страница 688: ...Rev 2 00 Jun 28 2007 Page 666 of 666 REJ09B0311 0200...
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Страница 692: ...H8SX 1650 Group Hardware Manual...