Many developers select an oscillator / resonator frequency that is at
or near the maximum value supported by a particular device.
This can be a mistake:
• Many application do not require the levels of performance
that a modern 8051 device can provide.
• The electromagnetic interference (EMI) generated by a
circuit increases with clock frequency.
• In most modern (CMOS-based) 8051s, there is an almost
linear relationship between the oscillator frequency and the
power-supply current. As a result, by using the lowest
frequency necessary it is possible to reduce the power
requirement: this can be useful in many applications.
• When accessing low-speed peripherals (such as slow
memory, or LCD displays), programming and hardware
design can be greatly simplified - and the cost of peripheral
components, such as memory latches, can be reduced - if the
chip is operating more slowly.
