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Section 19 Serial Communication Interface with FIFO (SCIF)
Rev. 4.00 Sep. 14, 2005 Page 746 of 982
REJ09B0023-0400
6. When Using the DMAC
Using an External Clock in Chock Synchronous Mode:
When using an external clock as the synchronization clock, after SCFTDR is updated by
the DMAC, an external clock should be input after at least five peripheral clock cycles. A
malfunction may occur when the transfer clock is input within four cycles after updating
SCFTDR (figure 19.20).
SCK
TDRE
TxD
D0
D1
D2
D6
D7
D3
D4
D5
t
Note: When the SCIF is operated on an external clock, set t > 4.
Figure 19.20 DMA Transfer Example in the Synchronization Clock
DMA Transfer Request:
When a DMA transfer is requested from the SCIF of which transfer request is allowed by
the DMAC, the transfer request from the SCIF is held in the DMAC. This transfer request
is cleared after it is actually transferred.
Even if the DME bit of the DMA operation register (DMAOR) and the DE bit of the DMA
channel control register (CHCR) are cleared, the DMA transfer request from the SCIF is
retained. In this state, note that the DMA transfer is done for one time without any DMA
transfer request from the SCIF when the DMAC allows the transfer request from the SCIF.
TEND Flag:
When the transmit FIFO data empty DMA transfer request is generated and the transmit
data is written to SCFTDR by the DMAC, the value indicated by the TEND flag is
undefined. Thus, do not use the TEND flag as a transmit end flag.
Содержание HD6417641
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Страница 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
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Страница 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Страница 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Страница 500: ...Section 13 Direct Memory Access Controller DMAC Rev 4 00 Sep 14 2005 Page 450 of 982 REJ09B0023 0400...
Страница 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Страница 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Страница 734: ...Section 18 Multi Function Timer Pulse Unit MTU Rev 4 00 Sep 14 2005 Page 684 of 982 REJ09B0023 0400...
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Страница 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
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Страница 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Страница 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
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