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LPC804 memory usage in functional-safety design

Question asked by Johan Forslöf on Jan 25, 2019
Latest reply on Jan 27, 2019 by jeremyzhou

Our design employs a LPC804 microcontroller within a functional-safety system. This raises a couple of low-level questions related to the behavior of the (to us) opaque ROM code and memory integrity.

 

1. How can we verify the integrity of the mask ROM code? Alternatively, is it possible to avoid ROM code usage after boot by directly programming the NVM and FRO?

 

2. Section 4.3.7.3 of UM11065 (rev 1.3, page 21) declares the ROM IAP calls as only using the top 4 bytes of RAM and unlike ISP does not mention stack usage. Conversely, section 4.5.17 (rev 1.3, page 34) states that 32-bytes of RAM are used. In an experiment 140 bytes of stack space was used in IAP programming. What is the maximum memory usage of IAP programming?

 

3. We would like to use the FLASH ECC correction as a declared measure for invariable memory errors. How can we show the correct functioning of the error correction mechanism?

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