[MPC5748G] Question about startup_MPC5748G.S file

キャンセル
次の結果を表示 
表示  限定  | 次の代わりに検索 
もしかして: 

[MPC5748G] Question about startup_MPC5748G.S file

ソリューションへジャンプ
827件の閲覧回数
kmh48301
Contributor IV

Hello.

I am working in "hello_world_mpc5748g" example project.

And I changed the "startup_MPC5748G.S" file in this example project.

Like this :

kmh48301_0-1611291921558.png

 

Original :  this startup code is making CTR register value 128

But I wanted to make CTR register value 127.

So, I changed the code like that.

 

The reason why I changed it is I need to reserve the memory address "0x4003_FFF0".

"Initialise SRAM ECC" part (I attatched) changed the value of address "0x4003_FFF0".

But I don't know the "Initialise SRAM ECC" part is for what..

 

So my question is 
1. Can I change the "Initialise SRAM ECC" part in Startup code? 

I worry some unexpected problem would be ocurred.

2. What does the "Initialise SRAM ECC" part in Startup code do? Please Explain more.

 

 

Thanks

Best regards

Phillip

0 件の賞賛
返信
1 解決策
817件の閲覧回数
lukaszadrapa
NXP TechSupport
NXP TechSupport

Hi Phillip,

here you can find the explanation:

lukaszadrapa_0-1611332610836.png

It is possible to retain some SRAM content through reset but it depends which reset occurred.

Resets which destroy RAM content:
1. Power on Reset 2. Destructive reset 3. Long functional reset (with MBIST enabled)
Ram content is unchanged on:
1. Short functional reset 2. Long functional reset (MBIST disabled)

So, it is necessary to check the type of reset (see MC_RGM module). If it was reset which destroyed the RAM content, it is necessary to initialize whole SRAM. If that reset didn't destroy the RAM, you can skip initialization on desired area.

Regards,

Lukas

 

元の投稿で解決策を見る

2 返答(返信)
779件の閲覧回数
kmh48301
Contributor IV

Thank you so much!!!!

0 件の賞賛
返信
818件の閲覧回数
lukaszadrapa
NXP TechSupport
NXP TechSupport

Hi Phillip,

here you can find the explanation:

lukaszadrapa_0-1611332610836.png

It is possible to retain some SRAM content through reset but it depends which reset occurred.

Resets which destroy RAM content:
1. Power on Reset 2. Destructive reset 3. Long functional reset (with MBIST enabled)
Ram content is unchanged on:
1. Short functional reset 2. Long functional reset (MBIST disabled)

So, it is necessary to check the type of reset (see MC_RGM module). If it was reset which destroyed the RAM content, it is necessary to initialize whole SRAM. If that reset didn't destroy the RAM, you can skip initialization on desired area.

Regards,

Lukas