mcf54455 Freescale Semiconductor, Inc, mcf54455 Datasheet - Page 25

• Manufacturer Part Number: mcf54455
• Description: 32-bit Microprocessor With Usb On-the-go, Ethernet, Pci, Ddr2/ddr Controller And Encryption
• Manufacturer: Freescale Semiconductor, Inc

Num
DD1
DD2
DD3
DD4
DD5
DD6
5.8
The following timing numbers must be followed to properly latch or drive data onto the SDRAM memory bus. All timing
numbers are relative to the four DQS byte lanes.
Freescale Semiconductor
Frequency of Operation
Clock Period
Pulse Width High
Pulse Width Low
Address, SD_CKE, SD_CAS, SD_RAS, SD_WE,
SD_CS[1:0] — Output Valid
Address, SD_CKE, SD_CAS, SD_RAS, SD_WE,
SD_CS[1:0] — Output Hold
Write Command to first DQS Latching Transition
SDRAM AC Timing Characteristics
FB_CSn, FB_BSn
FB_TSIZ[1:0]
FB_AD[31:0]
FB_A[23:0]
FB_CLK
FB_R/W
FB_OE
FB_TS
FB_TA
Characteristic
MCF5445x ColdFire
Table 13. SDRAM Timing Specifications
Figure 10. Flexbus Write Timing
FB1
FB2
FB4
®
Microprocessor Data Sheet, Rev. 0
Symbol
t
t
t
t
SDCKH
SDCKL
t
t
SDCK
DQSS
CMV
CMH
(1.0 x t
- 0.6ns
0.45
0.45
FB5
Min
7.5
2.0
—
—
SDCK
)
FB3
(0.5 x t
(1.0 x t
+ 1.0ns
+ 0.6ns
133.33
Max
0.55
0.55
—
—
Electrical Characteristics
SDCK
SDCK
)
)
t
t
Unit
MHz
SDCK
SDCK
ns
ns
ns
ns
Notes
3
25
1
2
3