The SDRAM self-refresh exit timing register
(SDSRETR) must be programmed second to satisfy the tXSR timing
requirement from the K4S641632H-TC(L)70 data sheet. Table 23-28 shows the calculation of the proper value to program into the T_XS field of this
register. Based on this calculation, a value of 6h must be written to the SDSRETR.
Figure 23-17 shows how the SDSRETR must be programmed.
Table 23-28 RR Calculation for EMIF to K4S641632H-TC(L)70 InterfaceField Name | Formula | Value from K4S641632H-TC(L)70 Data
Sheet | Value Calculated for Field |
---|
T_XS | T_XS >= (tXSR × fEM1CLK) - 1 | tRC = 68 ns (min)(1) | 6 |
(1) The Samsung data sheet does not specify a tXSR value.
Instead, Samsung specifies tRC as the minimum required time after CKE
going high to complete self-refresh exit.
Figure 23-17 SDRAM Self Refresh Exit Timing Register (SDR_EXT_TMNG)31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 |