In order to improve the quality of DDR2 waveform, we can configure the termination resistor value through
SDRAM_CONFIGURATION register / REG_DDR_TERM.
(0x6D00 0008, bit 26:24--> 0:0OHM 1:75OHM 2:150OHM 3:50OHM. )
Normally when we config different termination value(0/75/150/50 ohm) by this registor successfully,we can observe DDR2 clk wave changed obviously by oscilloscope.
(DDR2 clk wave changed including: rise/fall time change or overshoot/undershoot change)
Our problem:
change any termination value(0/75/150/50 ohm) in this registor will not lead to DDR2 clk wave changed.
It seems that this register hasn't been active.
So how to access this registor correctly?