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iMX6DQ LPDDR2 Initialization Issue

Question asked by rp123 on Sep 9, 2013
Branched to a new discussion

I am trying to configure LPDDR2 on a custom iMX6DQ board and am having issues. Every time I perform a read I get back something different and when I write I do not see it being stored.

 

(gdb) monitor mdw 0x80000000 8

0x80000000: 10e63e50 d13f3450 f43ec9c5 728b8190 080050cf 65507050 dc391598 0010f206

(gdb) monitor mww 0x80000000 0xffffffff

(gdb) monitor mdw 0x80000000 8

0x80000000: 100000ff 908b0050 08ffffc5 723f3490 ffb4c95e d1108184 d0395098 00507006

(gdb) monitor mdw 0x80000000 8

0x80000000: 10e660ff 10e66050 10e660c5 723f8190 08ffc95e d18b3484 ff00ff98 0050f206

(gdb) monitor mdw 0x80000000 8

0x80000000: 08e66050 72e62090 ffe6c9c5 d18b8150 d000ffff 003f3406 dcff1598 6510f284

(gdb) monitor mdw 0x80000000 8

0x80000000: 10e66050 d1e66050 ffe6ffc5 723f3490 08ffc9ff 658b8150 dc005098 00507006

(gdb) monitor mdw 0x80000000 8

0x80000000: ffe66050 d1e66050 080060c5 728b8190 dcffc9ff 653f3450 d0b4ff98 0010f206

 

The board is a single channel configuration using Micron’s DDR2 MT42L256M32D2LG-18 WT:A

I set the memory mapping mode to Dual channel (2x 32-bit), Fixed mapping (LPDDR2) (which starts from 0x80000000 and 0x10000000 -> 7FFFFFFFF is not used)

I then used a flyswatter2 and openocd tcl script to perform the DCD initializations. (attached to this email)

 

Am I supposed to reduce the clock speed before setting the DCD settings? ( I don’t see this done in any of your sample code but the LPDDR2 spec says something of the sort should be done)

Also I am unable to execute the following due to JTAG-DP STICKY ERROR

# Switch PL301_FAST2 to DDR Dual-channel mapping

mww 0x00B00000 0x1

 

What could be causing my reads to be corrupt? Could this be a delay/calibration issue? I have played around with my delay and impedance settings but am having the same issue.

 

Your input would be much appreciated

Thanks

Original Attachment has been moved to: lpddr2_mmdc_dcd_settings.txt.zip

Original Attachment has been moved to: jtag_init_script.cfg.zip

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