AM3352: VTP_CTRL register

Hiroyasu Tazawa1

Guru 12350 points

Part Number: AM3352

Hi, Everyone

I have a question about AM335x.

Can you tell me we should set vtp_ctrl register again before AM335x enter Stanby or Sleep ?

Best Regards
Hiroyasu

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

This register is part of the Control Module and should not be affected by transitions to Standby or DeepSleep modes.

0 Hiroyasu Tazawa1 over 8 years ago in reply to Biser Gatchev-XID

Guru 12350 points

Hi, Biser

Thank you for your reply.

We set bypass mode before enter stanby or deep sleep mode.
I understand We do not need to set vtp_ctrl register.

This understanding is correct?

Best Regards
hiroyasu

0 Hiroyasu Tazawa1 over 8 years ago in reply to Hiroyasu Tazawa1

Guru 12350 points

Hi, Biser

Could you reply?

Best Regards
Hiroyasu

0 Biser Gatchev-XID over 8 years ago in reply to Hiroyasu Tazawa1

TI__Guru**** 393215 points

If you modify this register before entering low-power modes, then you must restore its value for active mode on exiting low-power modes.

0 Hiroyasu Tazawa1 over 8 years ago in reply to Biser Gatchev-XID

Guru 12350 points

Hi, Biser

O.K. Thank you.
Can you tell me how to decide to value of vtp_ctrl register.
Do you have any reference value ?
I look for this value. but I do not see GEL and more.

Best Regards
Hiroyasu

0 Biser Gatchev-XID over 8 years ago in reply to Hiroyasu Tazawa1

TI__Guru**** 393215 points

You can check in the available SDKs, and also in the AM335x TRM Rev. O section 7.3.3.3.4.

0 Hiroyasu Tazawa1 over 8 years ago in reply to Biser Gatchev-XID

Guru 12350 points

Hi, Biser

I miss TRM. Thank you!

and I checked again below.

e2e.ti.com/.../1262826
processors.wiki.ti.com/.../AM335x_EMIF_Configuration_tips

I think this value is correct for DDR3 without Digital Filter.

//! Enable VTP
CONTROL_MODULE->VTP_CTRL = 0;
CONTROL_MODULE->VTP_CTRL = 6;
CONTROL_MODULE->VTP_CTRL |= (1 << 6);
CONTROL_MODULE->VTP_CTRL &= ~(1 << 0);
CONTROL_MODULE->VTP_CTRL |= (1 << 0);
//! Poll for VTP ready
while (!(CONTROL_MODULE->VTP_CTRL & (1 << 5)));

I understand user have to decice this Digital Filter value.

This understanding is correct ?

Best Regards
Hiroyasu

0 Biser Gatchev-XID over 8 years ago in reply to Hiroyasu Tazawa1

TI__Guru**** 393215 points

Yes, correct.

0 Hiroyasu Tazawa1 over 8 years ago in reply to Biser Gatchev-XID

Guru 12350 points

Hi,Biser

Thank you so much !

Best Regards
Hiroyasu

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AM3352: VTP_CTRL register