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Section 27
On-Chip RAM
Rev. 0.50 May 18, 2006 Page 1359 of 1588
REJ09B0313-0050
27.2 Usage
Notes
27.2.1 Page
Conflict
When the same page of the on-chip high-speed RAM is accessed from different buses
simultaneously, a conflict on the page occurs. Although each access is completed correctly, this
kind of conflict degrades the memory access speed. Therefore, it is advisable to provide software
measures to prevent such conflicts as far as possible. For example, no conflict will arise if
different pages are accessed by each bus.
27.2.2
RAME and RAMWE Bits
Before disabling memory operation or write access to the on-chip high-speed RAM through the
RAME or RAMWE bit, be sure to read from any address and then write to the same address in
each page; otherwise, the last written data in each page may not be actually written to the RAM.
// For page 0
MOV.L #H'FFF80000,R0
MOV.L @R0,R1
MOV.L R1,@R0
// For page 1
MOV.L #H'FFF84000,R0
MOV.L @R0,R1
MOV.L R1,@R0
// For page 2
MOV.L #H'FFF88000,R0
MOV.L @R0,R1
MOV.L R1,@R0
// For page 3
MOV.L #H'FFF8C000,R0
MOV.L @R0,R1
MOV.L R1,@R0
Figure 27.1 Examples of Read/Write
Содержание Single-Chip Microcomputer SH7203
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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 ...
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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 ...
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