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Method for Error Recovery Code Update on a Limited Size ROM Disclosure Number: IPCOM000182320D
Original Publication Date: 2009-Apr-27
Included in the Prior Art Database: 2009-Apr-27
Document File: 3 page(s) / 30K

Publishing Venue



A method for error recovery code update on a limited size ROM is disclosed. With this invention, we can improve the serviceability by optimizing the ROM usage and ensure the flash process well

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Method for Error Recovery Code Update on a Limited Size ROM

An algorithm can optimize the utilization of a limited size ROM with error recovery code update feature. Below is the detailed information we proposed.

1. Size limited situation, the project we are facing is to have only 128KB ROM size.
2. Error recovery, we need a reliability product and force us to have error recovery after a flash error. No matter it's a power loss or read/write failure.

Prior Art
We usually used in the PC or server industry by placing two ROMs and set either one as primary, the second one as the backup. This method is reliable but also a little cost consuming. (US # 5793943 or US # 6651188)

In current keyboard project, there is not too much budget for the ROM, and it has to be 128K size, the project split the ROM to half and set primary and backup. Here is the flow chart and briefing. But it's a little different than previous prior art that if we place two blocks into one ROM, we can't recovered by any physical error. (ROM body fail)


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Bit name Default Flash status bit complete Internal status bit incomplete

Power On

  Flash Command received

Initial Internal status bit to incomplete

flash status bit

Flash Map

Boot Loader



  Check if entering Flash Mode



Flash Process from Host to ROM_B

Internal status bit

set the flash status bit to complete



Copy ROM_B to ROM_A

Start to Run from ROM_A

Report to the host flash utility

Set Internal status bit = complete


Execute the code

The difficulty we've got right
ROM size is not optimized. For a 128KB size ROM, we can only have it spli...