AM6442: TMDS64EVM, MCU+SDK v9.1, CCS v12.6: why does NULL bootloader show A53 not running 1GHz ?

Prashant:

 There must have been some reason as to why the A53s installed onto EVMs in the Sitata product line (not just AM64x) were set to 800MHz and not at full speed 1GHz - we should ask why.  Someone probably had very good reason to not be able to test at 1GHz rate those cores.

 Also, the speeds on the MCU/MPU products are increasing. It would be smarter to start expressing those frequencies in KHz or MHz (and not have so many zeros)

thanks

Jim

ex-TIer '82-'97

Hi Jim,

I think it's just the MCU+ SDK that runs the A53 at 800 MHz. The Processor SDK runs them at their full speed as shown in the below logs. I guess the MCU+ SDK team might have some reasons to run them at 800 MHz by default.

root@am64xx-evm:~# k3conf --cpuinfo
|------------------------------------------------------------------------------|
| VERSION INFO                                                                 |
|------------------------------------------------------------------------------|
| K3CONF | (version 0.3-nogit built Fri Oct 06 12:20:16 UTC 2023)              |
| SoC    | AM64x SR2.0                                                         |
| SYSFW  | ABI: 3.1 (firmware version 0x0009 '9.1.8--v09.01.08 (Kool Koala))') |
|------------------------------------------------------------------------------|

|--------------------------------------------------------|
| Processor Name | Processor State | Processor Frequency |
|--------------------------------------------------------|
| A53SS0_CORE_0  | DEVICE_STATE_ON | 1000000000          |
| A53SS0_CORE_1  | DEVICE_STATE_ON | 1000000000          |
|--------------------------------------------------------|

Jim Mrowca said:

It would be smarter to start expressing those frequencies in KHz or MHz (and not have so many zeros)

I will give your feedback to the team. But it's very unlikely the team will be willing to change this as this will require performing a floating operation or they might already have some reasons to express in Hz only.

Regards,

Prashant

Hello Prashant,

Can we check with the team on the "why" of running the core frequency at 800MHz instead of 1GHz? Without context, I would expect that the processor cores ought to be set to their highest frequency settings to give the best results in benchmark tests.

Thanks,

Nick

Hello Nick,

On checking with the dev team, it seems there is no specific reason as such to run A53 cores at 800 MHz only. It's just that the team didn't validate the 1000MHz option.

Regards,

Prashant

Prashant, Nick: 

 Dependent on the IC speed grade, you can have A53 cores limited to 800MHz -- from sprsp56f

I look upon my EVMs and I see the XAM6442BS... so I should be able to run at the 1GHz rate on the EVM?

Put it another way, (from the first of Prashant's screenshots)

if I were to change the bootloader core info .defaultClockHz parameter to 1000*1000000 , would those MCU+SDK examples run on S grade ICs ? (would there be time before the v9.2 SDK releases to prove that?)

thanks

Jim