topic How to set CPU clock Correctly？ in MPC5xxx

How to set CPU clock Correctly？

zhangah — Fri, 22 Mar 2019 12:38:33 GMT

Hello,

My cpu is MPC5748G with Z4_0.According to the datasheet,the Cpu core clock can up to 160M(HZ).

my circuit is that:

When I use lwip_5748G demo project running in the core,the fasted bandwidth perform differently with diffrent CPU core clock setting.

the fault setting is like this:

On this case, the bandwidth can up to 3.9M.And the cpu timer is not accurate.

when I change the setting like this:

the bandwidth can only up to 1.2M.And the cpu timer is much more inaccurate compared with the default setting.

Can someone explain that condition for me ? And how could I set the CPU core clock and CPU bus clock correctly?

Thanks very much!

Re: How to set CPU clock Correctly？

lukaszadrapa — Tue, 26 Mar 2019 08:36:03 GMT

Hi,

the screenshot of your settings suggests that you are using very old version of SDK - I guess it is EAR 0.8.1, isn't it? The configuration has been changed and it could be the root cause. Currently there's version RTM2.0.0, so I would suggest to download latest Update 9:

S32 Design Studio IDE for Power Architecture based MCUs | NXP

Regards,

Lukas

Re: How to set CPU clock Correctly？

zhangah — Wed, 27 Mar 2019 07:42:30 GMT

Hello,

Thanks for your reply.Should I use the RTM2.0.0

My question is that Could I set the cpu core clock to 160M HZ ,while the freqency of the external Oscillators is 40M HZ ?

Re: How to set CPU clock Correctly？

lukaszadrapa — Wed, 27 Mar 2019 09:00:27 GMT

Hi,

yes, it's highly recommended to use the latest RTM version.

And yes, this will help to reach highest performance. By the way, this configuration is used in lwip demo code in RTM version 2.0.0.

Regards,

Lukas

Re: How to set CPU clock Correctly？

zhangah — Thu, 28 Mar 2019 07:46:05 GMT

Hello,

I have download the lastest update packet with the version of RTM 2.0.0 from nxp web station.

When I open the packet, there're several files like following:

There's no executable file. My OS is Windows 10. How could I use this packet to upgrade the SDK to RTM 2.0.0?

Could you give me a explicit Operation manual？ Thanks very much!

Re: How to set CPU clock Correctly？

lukaszadrapa — Thu, 28 Mar 2019 12:55:48 GMT

Hi,

see please this link, section Installation Instructions:

https://community.nxp.com/docs/DOC-342355

Regards,

Lukas

Re: How to set CPU clock Correctly？

zhangah — Fri, 29 Mar 2019 10:17:03 GMT

Hello,

Thanks for your help.Now I have completed the update.But Another question occur. How could I use the newer version SDK IDE to open the project developed by last version.Could you give me some guide manual? Thank you very much.

Re: How to set CPU clock Correctly？

lukaszadrapa — Fri, 29 Mar 2019 12:33:49 GMT

Hi,

if you used EAR 0.8.1, it will be necessary to start from scratch. It's not possible to migrate this project directly to latest RTM version. There are relatively lot of differences.

My colleague plan to write some "how to" document about the migration of projects but first EAR -> latest RTM is really not supported.

Regards,

Lukas

Re: How to set CPU clock Correctly？

zhangah — Tue, 02 Apr 2019 01:20:42 GMT

Hello,

Thanks for your help.It's a shame that Our project has almost completed in EAR 0.8.1.