I need the application note to use core time base (TBH,TBL) of MPC5777C

[ukirde_pramod]

I want to use the time base register of the core of MPC577C as a life long timer. Can you please provide any application note or example for the same?

[hongpingxu-b364]

Hi,

We checked the core reference manual and did certain test on the MPC5777C board, and then came to the following conclusion:

• The TBL reset value is random while cold powerup, and in warm powerup the reset value is unchanged.
• The timer base counts at system clock frequency.

Here are my answers.

1. Our concern is the init value when MCU powerup, “0” or one default value, or random value ?

Confirmed it is random on POR assertion.

2. If the value is “0”, how long time it can reach 0Xffffffff? 

3. If one default value, what’s the real value? Who set it? how long time it can reach 0Xffffffff?

Once the Time Base is enabled by setting the Time Base Enable (TBE) bit in the Hardware Implementation Register 0 (spr HID0), it counts at system clock frequency.

4. If it is one random value, how does it generate?

It is undefined on MCU POR assertion.

[hongpingxu-b364]

Hi David,

Could you please tell me:

1. The reset value of TBL when MCU powerup, “0” or one default value, or random value ?
2. If the value is “0”, how long time it can reach 0Xffffffff?
3. If one default value, what’s the real value? Who set it? how long time it can reach 0Xffffffff?
4. If it is one random value, how does it generate?

We find that the value is very large during SW initializing process all the ways.

BR,

Hornby

[davidtosenovjan]

Hi, timebase using you may find described in this example pack, specifically in the section 1:

https://www.nxp.com/docs/en/application-note/AN2865.pdf 

It is applicable with MPC5777C as well.