Minimum Microcontroller Coniguration
The minimum microcontroller configurations of the 8051- and AT89C2051- based microcontroller systems are shown in Figs 1.3 and 1.4. As can be seen
from these figures, only the following external components are required to have a working microcontroller:
We shall be using the circuit in Fig. 1.4 in all of the projects described in this book, except the last project which is based on a 40-pin device. The crystal chosen for the projects is 12 MHz, which gives a basic instruction timing of 1 fls. The power supply current of the AT89C2051 is around 15 mA, but a power supply which can deliver up to a few hundred milliamperes is recommended so that the interface circuitry attached to the microcontroller can be powered.