Timing configuration registers
| NCRC | configure Ncrc parameter in sdr50/104 mode, no more than 6. |
| PST_END_CMD_LOW_VALUE | configure cycles to lower cmd after voltage is changed to 1.8V. |
| PST_END_DATA_LOW_VALUE | configure cycles to lower data after voltage is changed to 1.8V. |
| SDCLK_STOP_THRES | Configure the number of cycles of module clk to judge sdclk has stopped |
| SAMPLE_CLK_DIVIDER | module clk divider to sample sdclk |