The SDRAM refresh control register (SDRAM_RCR) can
next be programmed to satisfy the required refresh rate of the K4S641632H-TC(L)70.
Table 25-29 shows the calculation of the proper value to program into the RR field of this
register. Based on this calculation, a value of 61Ah must be written to the
SDRAM_RCR. Figure 25-18 shows how the SDRAM_RCR must be programmed.
Table 25-29 RR Calculation for EMIF to K4S641632H-TC(L)70 Interface| Field Name | Formula | Values | Value Calculated for Field |
|---|
| RR | RR ≤ fEM1CLK × tRefresh Period / ncycles | From SDRAM data sheet: tRefresh Period = 64ms;
ncycles = 4096 EMIF clock rate: fEM1CLK =
100MHz | RR = 1562 cycles = 61Ah cycles |
Figure 25-18 SDRAM Refresh Control Register (SDRAM_RCR)| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 |
| 000 | 0 0110 0001 1010 (61Ah) |