DM36x DDR2 Drive Strength

Daisuke Maeda

Guru 20205 points

Is the description of Wiki below applied to DM36x?

http://processors.wiki.ti.com/index.php/DDR_Interface_Drive_Strength

Does the VTP calibration determine the drive strength automatically?

The VTP initialization sequence is described in the user guide.
How are other register fields that is not described in the sequence set?

Best regards,

Daisuke

over 11 years ago

0 Daisuke Maeda over 11 years ago

Guru 20205 points

Hi,

Please give me an answer as soon as possible.
Your prompt reply would be appreciated.

Best regards,

Daisuke

0 Brad Griffis over 11 years ago

TI__Guru*** 125430 points

Daisuke Maeda said:
Does the VTP calibration determine the drive strength automatically?

It sets the drive strength (output impedance) for the DM36x. Bitfields in the SDCR configure the DDR's drive strength.

Daisuke Maeda said:
How are other register fields that is not described in the sequence set?

See Section 3.2.3 Configuring SDRAM Timing Registers.

0 Daisuke Maeda over 11 years ago in reply to Brad Griffis

Guru 20205 points

Hi Brad,

Thank you for your reply.

I want to know how the VTP IO Control Register (VTPIOCR) is configured for the VTP calibration. However, the description of the initialization sequence in the User's Guide does not mention all fields in VTPIOCR.

How are other fields in VTPIOCR that is not mentioned configured? Should they be set to 0?

Best regards,

Daisuke

0 Brad Griffis over 11 years ago in reply to Daisuke Maeda

TI__Guru*** 125430 points

Please follow the procedure in Section 2.14.2 "Initializing Following Device Power Up and Device RESET". When the instructions say something like "Set bit CLRZ in VTPIOCR" that means that you perform a read, modify, write where you ONLY modify CLRZ. If the instructions don't mention a bitfield (e.g. VREFEN) then leave it at its default value.

0 Daisuke Maeda over 11 years ago in reply to Brad Griffis

Guru 20205 points

Hi Brad,

Thank you for your reply.

Best regards,

Daisuke

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DM36x DDR2 Drive Strength