LPC804 memory usage in functional-safety design

johan_forslof — Fri, 25 Jan 2019 13:41:08 GMT

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?

Re: LPC804 memory usage in functional-safety design

jeremyzhou — Mon, 28 Jan 2019 02:47:38 GMT

Hi Johan Forslöf,

Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
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?
-- No, I'm afraid not, the ROM code always starts firstly.
2) 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?
-- Yes, it's a bit confusing, 32-bytes RAM space is enough to satisfy a requirement of executing an ISP command.
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?
-- The operation of the ECC is transparent to the running application, this operation is automatical executed during any flash operations.

Hope this is clear.
Have a great day,
TIC

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LPC MicrocontrollersのトピックRe: LPC804 memory usage in functional-safety design

LPC804 memory usage in functional-safety design

Re: LPC804 memory usage in functional-safety design