1 termination example, 5 sdram overview, 1 sdram commands – Freescale Semiconductor MCF5480 User Manual
Page 457: Termination example -9, Sdram overview -9, Sdram commands -9
SDRAM Overview
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor
18-9
18.4.5.1
Termination Example
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.
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
LMR
H
L
L
L
L
LL
V
V
Load Extended Mode Register
LEMR
H
L
L
L
L
LH
V
V
CBR Auto Refresh
REF
H
L
L
L
H
X
X
X
MCF548X
DDR SDRAM
V
REF
25
Ω
50
Ω