MSC7116 Freescale Semiconductor / Motorola, MSC7116 Datasheet - Page 54

• Manufacturer Part Number: MSC7116
• Description: Low-Cost 16-bit DSP with DDR Controller and 10/100 Mbps Ethernet MAC
• Manufacturer: Freescale Semiconductor / Motorola

Hardware Design Considerations
3.5
MSC7116 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 37
54
Figure
•
•
Technique A
Technique B
RS = 22 Ω
RT = 24 Ω
36. 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
Chip Selects
Chip Selects
Controller
Controller
Command
Command
Address
Strobes
Address
Strobes
VREF
Mask
Mask
Data
Data
Figure 36. SSTL Termination Techniques
SSTL_2
SSTL_2
SSTL_2
SSTL_2
SSTL_2
SSTL_2
MSC7116 Data Sheet, Rev. 13
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