mcf5274l Freescale Semiconductor, Inc, mcf5274l Datasheet - Page 35

• Manufacturer Part Number: mcf5274l
• Description: Mcf5275 Integrated Microprocessor Family Hardware
• Manufacturer: Freescale Semiconductor, Inc

6.3
6.4
6.5
6.6
6.7
6.7.1
6.7.1.1
Table 21
Freescale Semiconductor
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Place the decoupling capacitors as close to the pins as possible, but they can be outside the
footprint of the package.
0.1uF and 0.01uF at each supply input
Use bus buffers on all data/address lines for all off-board accesses and for all on-board accesses
when excessive loading is expected. See electricals.
Use external pull-up resistors on unused inputs. See pin table.
Use a multi-layer board with a separate ground plane.
Place the crystal and all other associated components as close to the EXTAL and XTAL
(oscillator pins) as possible.
Do not run a high frequency trace around crystal circuit.
Ensure that the ground for the bypass capacitors is connected to a solid ground trace.
Tie the ground trace to the ground pin nearest EXTAL and XTAL. This prevents large loop
currents in the vicinity of the crystal.
Tie the ground pin to the most solid ground in the system.
Do not connect the trace that connects the oscillator and the ground plane to any other circuit
element. This tends to make the oscillator unstable.
Tie XTAL to ground when an external oscillator is clocking the device.
shows the behavior of SDRAM signals in synchronous mode.
Decoupling
Buffering
Pull-up Recommendations
Clocking Recommendations
Interface Recommendations
DDR SDRAM Controller
SDRAM Controller Signals in Synchronous Mode
MCF5275 Integrated Microprocessor Family Hardware Specification, Rev. 1.1
Preliminary
Design Recommendations
35