All, We are designing a "loader" for field firmware updates. Unfortunately we do not have the code space (P89C668) to have two sets of code in on-chip flash. Therefore we will use a scheme where we have the loader code located in sector one and all the ISRs in sector zero as the loader will use interrupts. The rest of the application will be in sectors 2 and up. The loader will erase the upper sectors and program the new code there. It will then erase sector zero and reprogram the vector table and the ISRs. Block one, the loader, will remain unchanged. Questions: I think I can locate the code in sector one and the ISRs in sector zero using user classes. I have done this with some ARM code in uVision. How can I be sure that the loader will have all the run-time modules it needs in sector zero? In other words, I cannot have the loader calling code in sectors that have been erased. It will have to be completely self contained except for the ISRs. Is this a reasonable plan? Anyone have a better way to do this? Rich
DO visualize wha will happen with your scheme if power fail at any time during the process. I have seen more dead chips due to this than anything else. If you decide to go ahead with a scheme where such can happen, at least socket your processor. Erik
Without the space to duplcate the code there is not much option.
then why not use NoTouch and the ISP Erik
The units are potted and on a 485 bus.
,i>The units are potted and on a 485 bus. on all such bopards, I have a connector to a "remote" MAX232equivalent just for ISP. Erik
When installed, the units are not accessible.
But the connectot I suggest will be
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