SDRAM Overview
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 18-9

18.4.5.1 Termination Example

Figure 18-5 shows the recommended termination circuitry for DDR SDRAM signals.
Figure 18-5. MCF548x DDR SDRAM Termination Circuit

18.5 SDRAM Overview

18.5.1 SDRAM Commands

When an internal bus master accesses SDRAM address space, the memory controller generates the
corresponding SDRAM command. Table 18-3 lists SDRAM commands supported by the memory
controller.
Table 18-3. SDRAM Commands
Function Symbol CKE CS RAS CAS WE BA[1:0] AP/C
MD Other A
Command Inhibit INH H H X X X X X X
No Operation NOP H L H H H X X X
Row and Bank Active ACTV H L L H H V V V
Read READ H L H L H V L V
Write WRITE H L H L L V L V
Precharge All Banks PALL H L L H L X H X
Load Mode Register LMRHLLLL LL V V
Load Extended Mode RegisterLEMRHLLLL LH V V
CBR Auto Refresh REF H L L L H X X X
MCF548X DDR SDRAM
VREF
25
50