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US006877062B2
(12) United States Patent ao) Patent No.: us 6,877,062 B2
Chen (45) Date of Patent: Apr. 5,2005
(54) METHOD AND APPARATUS FOR
INCREASING THE MEMORY READ/WRITE
SPEED BY USING INTERNAL REGISTERS
(75) Inventor: Chih-Yung Chen, Hsinchu (TW)
(73) Assignee: Winbond Electronics Corp., Hsinchu (TW)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 354 days.
(21) Appl. No.: 10/265,744
(22) Filed: Oct. 8, 2002
(65) Prior Publication Data
US 2003/0120854 Al Jun. 26, 2003 (30) Foreign Application Priority Data
Dec. 24, 2001 (TW) 90131964 A
(51) Int. CI.7 G06F 12/00
(52) U.S. CI 711/2
(58) Field of Search 711/2, 202
(56) References Cited
U.S. PATENT DOCUMENTS
5,237,699 A * 8/1993 Little et al 714/23
The present invention is a method and apparatus for increasing the memory read/write speed with special function registers (SFRs). This method comprises the steps of: (1) connecting additional external memory to the processor as expanded memory, (2) mapping the address of expanded memory to the unused SFR address in the processor, and (3) creating a control flag for switching the processor between the ICE mode or the normal mode. When in the ICE mode, the processor still uses extended instructions to perform read/write with expanded memory. Switching back to the normal mode, the processor can use the internal instructions to perform read/write with expanded memory. Using this method, built-in of an internal ICE and the slowing down of read/write during debugging due to the use of an external ICE can be eliminated.
7 Claims, 5 Drawing Sheets
