MSC7118 Freescale Semiconductor / Motorola, MSC7118 Datasheet - Page 52

• Manufacturer Part Number: MSC7118
• Description: Low-Cost 16-bit DSP with DDR Controller
• Manufacturer: Freescale Semiconductor / Motorola

Hardware Design Considerations
3.5
MSC7118 devices contain a memory controller that provides a glueless interface to external double data rate (DDR) SDRAM
memory modules with Class 2 Series Stub Termination Logic 2.5 V (SSTL_2). There are two termination techniques, as shown
in
Figure 33
52
Figure
•
•
Technique A
Technique B
RS = 22 Ω
RT = 24 Ω
32. Technique B is the most popular termination technique.
illustrates the power wattage for the resistors. Typical values for the resistors are as follows:
DDR Memory System Guidelines
MSC7118 Low-Cost 16-bit DSP with DDR Controller Data Sheet, Rev. 7
Chip Selects
Chip Selects
Controller
Controller
Command
Command
Address
Strobes
Address
Strobes
VREF
Mask
Mask
Data
Data
Figure 32. SSTL Termination Techniques
SSTL_2
SSTL_2
SSTL_2
SSTL_2
SSTL_2
SSTL_2
RS
RS
RS
RS
V
TT
Bank
DDR
Bank
DDR
Bank
DDR
Bank
DDR
Freescale Semiconductor
Generator
Generator
V
RT
RT
V
RT
RT
TT
TT