In microprocessors for a word to transfer between different

[ajith.mk91]

In microprocessors for a word to transfer between different registers(or between a register and a bus) an edge triggered pulse is required. Now in mp this can be done using control signal or a clock.In 8085 mp for what peripherals is that trigger provided by clock and what peripherals is that trigger provided by control signal. For example in a text which i follow it is stated that the data is latched from memory on to the data bus during memory read machine cycle's control signal(MEMR) transition. In another instant it is stated that clock provides that trigger during the T-states. Which is correct?

 

[anorlunda]

For example in a text which i follow it is stated that the data is latched from memory on to the data bus during memory read machine cycle's control signal(MEMR) transition.

Even that method is controlled by phases of the clock. If you design logic by detecting conditions, then generating a trigger, you accumulate delays. Using clocks avoids accumulating delays, but you must be conservative and allow for the worst case.