Chapter 8 The Counter

Another useful function is the counter. This chapter defines an 8-bit counter with all the bells and whistles. The counter described here has two asynchronous inputs—reset and preset. It has three synchronous inputs—up/down control, count enable, and load enable. There is also a carry output. If there’s anything else someone would need in a counter, I can’t think of it. The schematic representation of this counter is shown in Figure 8-1.

Figure 8-1 An up/down counter.

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Note that I have not specified the priority of the different control signals. This is not apparent from the schematic. Here is an area where problems can ...

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