Page 111 - Embedded Microprocessor Systems Real World Design

Make sure the crystal type matches the system specifications. If you are using an
external oscillator, make sure it matches duty cycle and drive-level requirements
of the microprocessor.
Verify that bus loading is not exceeded.
Verify that loading of 1/0 port pins is not exceeded (either sinking or sourcing
current).
Venfy that inputs to timers meet frequency and duty-cycle limitations of the part.
This usually depends on the microprocessor or timer IC clock speed.
If bus buffers are needed, make sure that each buffer is enabled only when the
peripherals it is accessing are selected. Watch for bus conflicts from turning the
buffer on too early or turning it off too late. Account for buffer delays in timing
calculations.
Avoid bus contention between peripherals.
Make sure wait-state timing gets wait requests asserted in time.
Make sure that the WDT functionality matches system requirements.
Make sure the internal peripherals are compatible with your requirements.
Make sure the DMA controller logic can handle back-teback accesses.
Make sure you take EMC requirements into consideration.

Chapter 3 will cover additional hardware design topics as well as a hardware
specification outline.

Hardware Design 1 93