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8-18
MPC8240 Integrated Processor User’s Manual
DMA Register Descriptions
The values in the PRC field are used as follows:
•
If PRC = 00 (PCI read), then all DMA reads from PCI use the PCI read command.
•
If PRC = 01 (PCI read line), then the PCI read line command is used if the PCLSR
(see Section 4.2.5, “PCI Cache Line Size—Offset 0x0C) is programmed for 32-byte
cache lines, and the current DMA transfer is for at least two 32-bit transactions.
Otherwise, PCI read commands are used.
•
If PRC = 10 (PCI read multiple), then the PCI read multiple command if used if the
PCLSR is programmed for 32-byte cache lines, the current DMA transfer is aligned
on a cache line address, and more than one full cache line of data is to be transferred.
Otherwise, if the current DMA transfer is for at least two 32-bit transactions (and
less than or equal to one cache line), then the read line command is used. If the
conditions for using the PCI read line command above are not met, then the PCI read
command is used.
8.7.2 DMA Status Registers (DSRs)
The DSRs report various DMA conditions during and after the DMA transfer. Writing a 1
to a set bit clears the bit. Software attempting to determine the source of interrupts should
always perform a logical AND function between the bits of the DSR and their
corresponding enable bits in the DMR and CDAR. Figure 8-5 shows the bits in the DSRs.
Figure 8-5. DMA Status Register (DSR)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
00
0
31
8
7
6
5
4
3
2
1
0
Reserved
LME
PE
CB
EOSI
EOCAI
Содержание MPC8240
Страница 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Страница 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Страница 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Страница 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Страница 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Страница 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Страница 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Страница 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Страница 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Страница 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Страница 516: ...16 14 Watchpoint Trigger Applications ...
Страница 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Страница 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Страница 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...