i.MX6DQ LPDDR2 Register Programming Aid

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i.MX6DQ LPDDR2 Register Programming Aid

i.MX6DQ LPDDR2 Register Programming Aid

This is a detailed programming aid for the registers associated with MMDC initialization. The last sheet formats the register settings for use with ARM RealView ICE. It can also be used with the windows executable for the DDR Stress Test. This programming aid was used for internal Freescale validation boards.


Register MMDC_MAARCR is not normally programmed by the initialization script. Freescale recommends leaving it with default values.

This is an advisory to customers who decide to change some of the fields in this register.

A bug has been found with the ARCR_GUARD field. It should always be left programmed to the default 0x0 value. If programmed to a different value, the behavior is unpredictable.

Hi Mark,

it appears that in the formula to calculate CS0_END (channel 0) an offset of 2048Mbytes is used instad of the correct 256MBytes:

((((C19*1024*1024*1024)/8+ 2048*1024*1024)/(32*1024*1024))-1)



Field D67 is used to enable the 2nd chip select if there are 2 channels.   I believe it should be


The original is compared to C20, which is Chip selects per channel.  C21 is number channels.

2048 is right for Channel 0.  Channel 1 is 256.

Field D67 is to enable a second chip select, not to enable another channel.  Each channel can have one or two chip selects and field D67 simply enables the second chip select for each channel.  The control to enable two channels is in register MDMISC.LPDDR2_2CH.  Therefore, the equation in the RPA for field D67 is correct.  

Ah, thanks.  That clarifies the meaning of those registers.  The table as downloaded configures my memory so I can boot my custom board but I only get 1/2 of the expected total ram (I see 512MiB in U-boot/Linux instead of 1GiB) available after I boot.  Enabling the 2nd chip select fixed that but I'm not confident it is fixed correctly.  I'll continue to investigate.  

Mem config: 

 4 Gb/ Channel

 1 CS/Channel

 2 Channel

Total 8Gb or 1GiB.

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Last update:
‎06-24-2015 10:11 PM
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