Hitachi 237
9.3.2
DMA Transfer Requests
DMA transfer requests are usually generated in either the data transfer source or destination, but
they can also be generated by devices that are neither the source nor the destination. Transfers can
be requested in three modes: auto-request, external request, and on-chip peripheral module
request. The request mode is selected in the AR bit of the DMA channel control registers 0 and 1
(CHCR0, CHCR1) and the RS0 and RS1 bits of the DMA request/response selection control
registers 0 and 1 (DRCR0, DRCR1).
Table 9.3
Selecting the DMA Transfer Request Using the AR and RS Bits
CHCR
DRCR
AR
RS1
RS0
Request Mode
Resource Select
0
0
0
Module request mode DREQ external request (external request mode)
0
1
RXI (SCI receive) request
1
0
TXI (SCI transmit) request
1
X
X
Auto request mode
Auto Request: 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 of CHCR0 and CHCR1 and the DME bit of the DMA
operation register (DMAOR) are set to 1, the transfer begins (so long as the TE bits of CHCR0
and CHCR1 and the NMIF and AE bits of DMAOR are all 0).
External Request: In this mode a transfer is started by a transfer request signal (DREQ) from an
external device. Choose one of the modes shown in table 9.4 according to the application system.
When DMA transfer is enabled (DE = 1, DME = 1, TE = 0, NMIF = 0, AE = 0), a transfer is
performed upon input of a DREQ.
Содержание SH7095
Страница 1: ...SH7095 Hardware User Manual ...
Страница 16: ...Hitachi 5 1 2 Block Diagram Figure 1 1 is a block diagram of the SH7095 Figure 1 1 Block Diagram ...
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Страница 105: ...94 Hitachi Figure 5 14 Pipeline Operation when Interrupts are Enabled by Changing the SR ...
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Страница 152: ...Hitachi 141 Figure 7 8 Example of 32 Bit Data Width SRAM Connection ...
Страница 157: ...146 Hitachi Figure 7 13 Synchronous DRAM 32 bit Device Connection ...
Страница 161: ...150 Hitachi Figure 7 15 Basic Burst Read Timing Auto Precharge ...
Страница 167: ...156 Hitachi Figure 7 20 Burst Read Timing Bank Active Same Row Address ...
Страница 168: ...Hitachi 157 Figure 7 21 Burst Read Timing Bank Active Different Row Addresses ...
Страница 169: ...158 Hitachi Figure 7 22 Write Timing No Precharge ...
Страница 170: ...Hitachi 159 Figure 7 23 Write Timing Bank Active Same Row Address ...
Страница 178: ...Hitachi 167 a Phase Shifted 90 by PLL b Phase Shift Using PLL is 0 Figure 7 28 Phase Shift with the PLL ...
Страница 180: ...Hitachi 169 Figure 7 29 Example of a DRAM Connection 32 Bit Data Width ...
Страница 190: ...Hitachi 179 Figure 7 36 Example of Pseudo SRAM Connection 1 M pseudo SRAM ...
Страница 191: ...180 Hitachi Figure 7 37 Example of Pseudo SRAM Connection 4 M pseudo SRAM ...
Страница 209: ...198 Hitachi Figure 7 50 Master and Partial Share Master Connections ...
Страница 218: ...Hitachi 207 EX Instruction execution MA Memory Access WB Write back Figure 8 3 Reading during a Cache Hit ...
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Страница 307: ...296 Hitachi Note For a CPU writing H AA55 to FRC Figure 11 2 FRC Access Operation Write ...
Страница 308: ...Hitachi 297 Note For an FRC reading from a CPU H AA55 Figure 11 3 FRC Access Operation Read ...
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Страница 370: ...Hitachi 359 Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data ...
Страница 371: ...360 Hitachi Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data cont ...
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Страница 402: ...Hitachi 391 Figure 15 6 PLL Synchronization Settling Timing ...
Страница 405: ...394 Hitachi Figure 15 7 Reset Input Timing Figure 15 8 Interrupt Signal Input Timing With PLL1 Off ...
Страница 408: ...Hitachi 397 Figure 15 13 Bus Release Timing Slave Mode With PLL1 Off ...
Страница 436: ...Hitachi 425 Figure 15 33 Synchronous DRAM Mode Register Write Cycle TRP 1 Cycle ...
Страница 437: ...426 Hitachi Figure 15 34 Synchronous DRAM Mode Register Write Cycle TRP 2 Cycles ...
Страница 439: ...428 Hitachi Figure 15 36 Synchronous DRAM Auto Refresh Cycle Shown From Precharge Cycle TRP 1 Cycle TRAS 2 Cycles ...
Страница 449: ...438 Hitachi Figure 15 46 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL On ...
Страница 454: ...Hitachi 443 Figure 15 51 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL Off ...
Страница 461: ...450 Hitachi Figure 15 58 Pseudo SRAM Auto Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Страница 462: ...Hitachi 451 Figure 15 59 Pseudo SRAM Self Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Страница 467: ...456 Hitachi Figure 15 64 Pseudo SRAM Auto Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Страница 468: ...Hitachi 457 Figure 15 65 Pseudo SRAM Self Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Страница 471: ...460 Hitachi Figure 15 68 Interrupt Vector Fetch Cycle PLL On No Waits ...
Страница 472: ...Hitachi 461 Figure 15 69 Interrupt Vector Fetch Cycle PLL Off No Waits ...
Страница 473: ...462 Hitachi Figure 15 70 Interrupt Vector Fetch Cycle 1 External Wait Cycle ...
Страница 474: ...Hitachi 463 Figure 15 71 Address Monitor Cycle ...
Страница 490: ...Hitachi 479 B 2 Register Chart ...