Tc234 mcu clock

[Ikavalis]

Hello.

I am sorry if this is not the right place to ask this or if my question is a bit vague.

I am trying to configure the clock frequency on an evaluation triboard that has a tc234 on. I have managed to configure this without the use of iLLD functions (for learning purposes and in the future I want to be as independent as possible).

During the tests I conducted I found out that when the system starts up, the system already starts in normal pll mode and is basically configured exactly as I need it to, instead of starting in free running as the manual suggests.

My question is how is this done? Isn't it supposed to start with the backup clock instead of using the external crystal?

I would be thankful for some insight regarding this pre-co figuration.

Thank you in advance.

[Prudhvi_E]

Hi,

The TC2xx devices have the following configuration during the startup:

fSRI= fCPU0 = fFSI=fBACK=100MHz nominal
fSPB=fSTM=fBACK/2=50MHz nominal

Could you also clarify following queries:

1. At which part of System Initialization are you testing and observing that PLL in normal mode? 

2. Could you please share your startup code?

Regards,

Prudhvi.

[Ikavalis]

Hello,

Thank you for your reply.

Yes, these are the values that I was expecting, but instead I get fPLL = 200Mhz and fSPB = 100Mhz.

The clock is configured to run on external crystal with f = 20Mhz in normal mode.

Turns out there's this code here that is doing the initialization:

#define IFXCPU_CSTART_CCU_INIT_HOOK() (void)IfxScuCcu_init(&IfxScuCcu_defaultClockConfig); /*The status returned by Ccu init is ignored */

It is located under Libraries\iLLD\TC234\Tricore\Cpu\CStart\IfxCpu_CStart0.c

I am not completely sure why this exists and why it is initializing like this.

[Prudhvi_E · Accepted solution]

Hi,

The function "IfxScuCcu_init" initializes the Clock for maximum performance by changing the frequency to higher value.

You may comment the function if you don't need to change the frequency or call the function IfxScuCcu_init with the Clock configuration as per your need.

Regards,

Prudhvi.