SDRAM Information

[lpcware]

Content originally posted in LPCWare by schisanoa on Sat Apr 05 07:49:07 MST 2014
Hi, I'm developing a project with the LPC4078 parts, and I'm using the same RAM memory as in the Embedded Artists Development kit(256Mbit), I'm also using the same example code of the LPCOpen for RAM initializing and EMC management, ecc...

In some other thread I read that the SDRAM should be calibrated, someone could help me understanding if I need to calibrate SDRAM also I use the same code in the LPCOpen package and what is the SDRAM Calibration?

Sorry for my question if it may be stupid question for someone but I want to do everything in the best manner.

Thank to everybody help me

[lpcware]

Content originally posted in LPCWare by schisanoa on Mon Apr 07 05:59:54 MST 2014
OK Wolfgang, thank you.

But this RAM calibration is always required or only if I need to go over a certain frequency?

[lpcware]

Content originally posted in LPCWare by wmues on Mon Apr 07 02:07:10 MST 2014
I am using the LPC1788, and Initialisation of the SDRAM is as follows:

1) Init EMC and SDRAM.
2) Init delay lines to default values.
3) Using a RAM test function, iterate through the delay lines and determine min/max values.
4) Set delay lines to middle values, and store these values at a safe place.
5) measure the delays with the on-chip measurement hardware and store these values at a safe place.
6) Program the MPU if you want to execute code from SDRAM.

7) In regular intervals, do the following recalibration:
  a) measure the current delays with on-chip hardware.
  b) calculate new values for the delay lines from (original values, original measured values, current measurement).

regards
Wolfgang