We just don’t have enough words to go around. Latches have synchronous and asynchronous inputs. Inputs that work in relation to a clock pulse are synchronous. “J”, “K” and “D” inputs, for example, cause nothing to happen themselves. They require a clock pulse. Inputs that cause an immediate result are asynchronous. “Set”, “Reset”, “Clear” and such are typical asynchronous inputs. In general asynchronous inputs override synchronous inputs. Simple enough.
Then there are synchronous and asynchronous counters that both require a clock pulse. Synchronous counters implies that all the counter outputs change state at the same time, triggered by a single clock pulse. Asynchronous counters, ripple counters, change state in sequence. Lower stages changing state cause upper stages to change state. The count ripples up through the stages. In ripple counters there may be a period of some 50 ns where the outputs are not a valid count and can cause glitches in operation.
All that being said a synchronous or asynchronous counter can have a certain function be synchronous or asynchronous. A common clear input or presettable inputs may be synchronized to the counting clock pulse or be asynchronous.
Synchronous serial communication implies that a separate clock pulse is used to control the timing of the data bits. Absolute speed is not so much a concern. Asynchronous serial communication implies that data bits are sent at a specified time frame. Speed is very important.
In synchronous communications data speeds can be slowed down to the speed of manual switch operations. In asynchronous communication systems the speed at which data is sent must be organized so it is received at the same speed.
Then there are synchronous and asynchronous counters that both require a clock pulse. Synchronous counters implies that all the counter outputs change state at the same time, triggered by a single clock pulse. Asynchronous counters, ripple counters, change state in sequence. Lower stages changing state cause upper stages to change state. The count ripples up through the stages. In ripple counters there may be a period of some 50 ns where the outputs are not a valid count and can cause glitches in operation.
All that being said a synchronous or asynchronous counter can have a certain function be synchronous or asynchronous. A common clear input or presettable inputs may be synchronized to the counting clock pulse or be asynchronous.
Synchronous serial communication implies that a separate clock pulse is used to control the timing of the data bits. Absolute speed is not so much a concern. Asynchronous serial communication implies that data bits are sent at a specified time frame. Speed is very important.
In synchronous communications data speeds can be slowed down to the speed of manual switch operations. In asynchronous communication systems the speed at which data is sent must be organized so it is received at the same speed.