MPC8360E DDR Calibration

[gordycarlson320]

Using the MPC 8360 processor.  Our question concerns the DDR Impedance calibration. 

1. Is it recommended to use the Automatic hardware Calibration, or the manual software calibration algorithm referenced in MPC8360ERM Rev. 3 (section 5.4.3.8)?
2. What is the power up value of the DDRCDR register?  I was unable to find it in the manuals.
3. The manual previously referenced does not indicate if the DDRDSR can be checked when using the Automatic hardware calibration to see if the Automatic Hardware calibration appears to be working.  Can it be used, or is there another method to determine what the Automatic Hardware calibration is setting the impedance to?

Gordy Carlson

[Bulat]

1. It is up to the user. Automatic calibration was specially implemented to get the process faster/easier. SW override allows to set different output impedance values, e.g. to use fine tuning for your particular DDR system. Automatic calibration always sets value close to 18 Ohm.
2. DDRCDR is 0x730400001 at reset. Can be found, for example, in table 5-33.
3. DDRDSR always shows current impedance, for example after automatic calibration.

Regards,

Bulat

[gordycarlson320]

An additional question... Is there a recommended (or preferred) way to calibrate the DDR?....ie.. – automatic hardware calibration of the DDR impedance, or manual software calibration of the DDR impedance?