Appendix B. Buffering and Impedance Matching
B-1
Appendix B
Buffering and Impedance Matching
When required:
•
SDRAM and a large number of external peripherals are required for a particular
system configuration.
•
Some peripherals may have excessive input capacitance.
•
Minimize signal reflections at higher clock speeds.
•
Minimize capacitive loading on signals to SDRAMs.
•
Operation of MCF5272 at highest frequencies, i.e. 66MHz, requires clean signals
to ensure setup and hold times are met and to minimize EMC noise in terms of
overshoot and undershoot of signals.
What to do:
•
Add buffers on address and control signals shared by SDRAM and other
peripherals.
•
NEVER put buffers between the MCF5272 device and the SDRAMs.
•
Put termination resistors as close as possible to outputs.
•
Or use buffers that have integral termination resistors.
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...