Skip to main content
swu.1
Associate
December 29, 2022
Solved

Why RAM and System RAM shall be reset when system boot up?

  • December 29, 2022
  • 4 replies
  • 2079 views

Hi expert,

I am using Stellar SR6 P7 line, e.g. SR6P7C8. According to the SDK there is RAM and System RAM reset operation when system boot,

/* Initialize memories protected by ECC */
 bl _raminit
 bl _sysraminit

I want to get more information about clearing memories for ECC. Why these step are needed? Is this for DAN-0055942?

Thanks.

This topic has been closed for replies.
Best answer by Tesla DeLorean

>>Why these step are needed?

Well presumably the MCU can start with all manner of random bits in the data lines and the ecc/hamming bits. Odds are just reading memory will result in a fault.

You zero memory to establish a workable baseline, because the system doesn't clear the memory automatically.

4 replies

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
December 29, 2022

>>Why these step are needed?

Well presumably the MCU can start with all manner of random bits in the data lines and the ecc/hamming bits. Odds are just reading memory will result in a fault.

You zero memory to establish a workable baseline, because the system doesn't clear the memory automatically.

Tips, Buy me a coffee, or three.. PayPal VenmoUp vote any posts that you find helpful, it shows what's working..
swu.1
swu.1Author
Associate
December 29, 2022

Thanks for your update.

CAyde.1
Visitor II
February 14, 2023

Resetting RAM and system RAM during system boot up helps to clear any leftover data or instructions that may be stored in memory from previous sessions or processes. This ensures that the system starts with a clean slate and is not affected by any stray data or instructions that could cause errors or instability. Additionally, resetting RAM can help to optimize system performance by freeing up memory that may have been occupied by unnecessary or outdated data.

https://goappsplay.com/

Giuseppe DI-GIORE
ST Employee
May 9, 2023

The RAM is protected by Error Code Correction (ECC).

In order to start ECC, the RAM has to be set to a known value on startup, usually zero.

Just for introduction to ECC, see AN4276.

Regards,

Giuseppe