Part Number: AM3703
Hello,
I have problem with new parts of Micron DDR (MT29C4G48MAZBAAKS) memories in my system. It works only at 83Mhz of L3_ICLK.
Regarding TRM document CONTROL_PROG_IO0 register sets the DS:
Drive strength for output load:
0x0: Load range = [2 pF-4 pF]
0x1: Load range = [4 pF-12 pF]
I try to tune the impedance matching using CONTROL_PROG_IO0 by changing the drive strength for SDRC pins (CONTROL_PROG_IO0 = 0xFC00 0000) but I measure with the oscilloscope the DDR signals shapes and there is no any changes on signals.
When I try the DDR memory's Driver Strength configuration , half strength for example (SDRC_EMR2_0 = 0x20) then amplitude of the signals reduces immediately.
I also tried to change the pull-up/down configuration of DDR data pins' registers (CONTROL_PADCONF_SDRC_Dxx) but again there is no any effect on signals.
I change the registers from u-boot with commands ;
for CONTROL_PROG_IO0: mw 48002444 FC000000
for SDRC_EMR2_0: mw 6D00008C 20
Can someone explain me , why CONTROL_PROG_IO0 not effects the drive strength of DDR connections?
