Section 10 Direct Memory Access Controller (DMAC)
Rev. 0.50 May 18, 2006 Page 402 of 1588
REJ09B0313-0050
10.4.2
DMA Transfer Requests
DMA transfer requests are basically generated in either the data transfer source or destination, but
they can also be generated in external devices and on-chip peripheral modules that are neither the
transfer source nor destination.
Transfers can be requested in three modes: auto request, external request, and on-chip peripheral
module request. The request mode is selected by the RS[3:0] bits in CHCR_0 to CHCR_7 and
DMARS0 to DMARS3.
(1) Auto-Request
Mode
When there is no transfer request signal from an external source, as in a memory-to-memory
transfer or a transfer between memory and an on-chip peripheral module unable to request a
transfer, the auto-request mode allows the DMAC to automatically generate a transfer request
signal internally. When the DE bits in CHCR_0 to CHCR_7 and the DME bit in DMAOR are set
to 1, the transfer begins so long as the TE bits in CHCR_0 to CHCR_7, and the AE and NMIF bits
in DMAOR are 0.
(2) External
Request
Mode
In this mode a transfer is performed at the request signals (DREQ0 to DREQ3) of an external
device. Choose one of the modes shown in table 10.5 according to the application system. When
the DMA transfer is enabled (DE = 1, DME = 1, TEMASK = 0 or 1 (TE = 0 when TEMASK = 0),
AE = 0, NMIF = 0 for level detection; DE = 1, DME = 1, TE = 0, AE = 0, NMIF = 0 for edge
detection), DMA transfer is performed upon a request at the DREQ input.
Table 10.5 Selecting External Request Modes with the RS Bits
RS[3] RS[2] RS[1] RS[0] Address
Mode
Transfer
Source
Transfer
Destination
0 0 0 0 Dual
address
mode
Any
Any
0 External
memory,
memory-mapped
external device
External device with
DACK
0 0 1
1
Single address mode
External device with
DACK
External memory,
memory-mapped
external device
Содержание Single-Chip Microcomputer SH7203
Страница 2: ...Rev 0 50 May 18 2006 Page ii of xxx ...
Страница 30: ...Rev 0 50 May 18 2006 Page xxx of xxx ...
Страница 52: ...Section 1 Overview Rev 0 50 May 18 2006 Page 22 of 1588 REJ09B0313 0050 ...
Страница 98: ...Section 2 CPU Rev 0 50 May 18 2006 Page 68 of 1588 REJ09B0313 0050 ...
Страница 128: ...Section 4 Clock Pulse Generator CPG Rev 0 50 May 18 2006 Page 98 of 1588 REJ09B0313 0050 ...
Страница 200: ...Section 6 Interrupt Controller INTC Rev 0 50 May 18 2006 Page 170 of 1588 REJ09B0313 0050 ...
Страница 242: ...Section 8 Cache Rev 0 50 May 18 2006 Page 212 of 1588 REJ09B0313 0050 ...
Страница 400: ...Section 9 Bus State Controller BSC Rev 0 50 May 18 2006 Page 370 of 1588 REJ09B0313 0050 ...
Страница 668: ...Section 11 Multi Function Timer Pulse Unit 2 MTU2 Rev 0 50 May 18 2006 Page 638 of 1588 REJ09B0313 0050 ...
Страница 696: ...Section 13 Watchdog Timer WDT Rev 0 50 May 18 2006 Page 666 of 1588 REJ09B0313 0050 ...
Страница 726: ...Section 14 Realtime Clock RTC Rev 0 50 May 18 2006 Page 696 of 1588 REJ09B0313 0050 ...
Страница 796: ...Section 15 Serial Communication Interface with FIFO SCIF Rev 0 50 May 18 2006 Page 766 of 1588 REJ09B0313 0050 ...
Страница 876: ...Section 17 I2 C Bus Interface 3 IIC3 Rev 0 50 May 18 2006 Page 846 of 1588 REJ09B0313 0050 ...
Страница 1020: ...Section 19 Controller Area Network RCAN TL1 Rev 0 50 May 18 2006 Page 990 of 1588 REJ09B0313 0050 ...
Страница 1054: ...Section 21 D A Converter DAC Rev 0 50 May 18 2006 Page 1024 of 1588 REJ09B0313 0050 ...
Страница 1226: ...Section 23 USB 2 0 Host Function Module USB Rev 0 50 May 18 2006 Page 1196 of 1588 REJ09B0313 0050 ...
Страница 1294: ...Section 24 LCD Controller LCDC Rev 0 50 May 18 2006 Page 1264 of 1588 REJ09B0313 0050 ...
Страница 1386: ...Section 26 I O Ports Rev 0 50 May 18 2006 Page 1356 of 1588 REJ09B0313 0050 ...
Страница 1512: ...Section 30 List of Registers Rev 0 50 May 18 2006 Page 1482 of 1588 REJ09B0313 0050 ...
Страница 1598: ...Section 31 Electrical Characteristics Rev 0 50 May 18 2006 Page 1568 of 1588 REJ09B0313 0050 ...
Страница 1606: ...Appendix Rev 0 50 May 18 2006 Page 1576 of 1588 REJ09B0313 0050 ...
Страница 1618: ...Rev 0 50 May 18 2006 Page 1588 of 1588 REJ09B0313 0050 ...
Страница 1621: ......
Страница 1622: ...SH7203 Group Hardware Manual ...