MCF52274 FREESCALE [Freescale Semiconductor, Inc], MCF52274 Datasheet - Page 23

• Manufacturer Part Number: MCF52274
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

5.7.2
The SDRAM controller supports accesses to main SDRAM memory from any internal master. It supports either standard
SDRAM or double data rate (DDR) SDRAM, but it does not support both at the same time.
5.7.2.1
The following timing numbers indicate when data will be latched or driven onto the external bus, relative to the memory bus
clock, when operating in SDR mode on write cycles and relative to SD_DQS on read cycles. The device’s SDRAM controller
is a DDR controller that has an SDR mode. Because it is designed to support DDR, a DQS pulse must still be supplied to the
device for each data beat of an SDR read. The processor accomplishes this by asserting a signal named SD_SDR_DQS during
Freescale Semiconductor
SDRAM Bus
SDR SDRAM AC Timing Specifications
FB_CSn, FB_BE/BWEn
FB_CSn, FB_OE,
FB_BE/BWEn
MCF5227x ColdFire
FB_D[31:X]
FB_D[31:X]
FB_A[23:0]
FB_A[23:0]
Preliminary—Subject to Change Without Notice
FB_CLK
FB_R/W
FB_CLK
FB_R/W
FB_OE
FB_TS
FB_TS
FB_TA
FB_TA
Figure 10. FlexBus Read Timing
Figure 11. Flexbus Write Timing
FB1
FB1
ADDR[31:X]
ADDR[31:X]
S0
S0
®
FB2
FB2
Microprocessor Data Sheet, Rev. 6
FB6
FB6
ADDR[23:0]
ADDR[23:0]
S1
S1
DATA
DATA
FB4
S2
S2
FB7
FB7
FB5
S3
S3
FB3
FB3
Electrical Characteristics
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