Control signals

Control signals are mostly produced by a microprocessor. They enforce specific actions in addressed blocks or define the direction of information flow.

The most important control signals are the signals WR (record) and RD (reading). They define the direction of the information flow. Record - from the microprocessor, and reading to the microprocessor. Bardzo ważny jest sygnał RST - resets the microprocessor and all associated circuits. It is always displayed when the microcomputer is turned on, after determining the supply voltages. I / O circuits can produce a special kind of control signal. This is the interrupt signal - INT. This signal is used as a feedback loop in a microcomputer. The occurrence of this signal modifies the operation of the microcomputer, which automatically starts the implementation of the so-called. interrupt handler. However, no spontaneity - a programmer must predict everything when writing a microcomputer operation program.

Another microcomputer structure is called Harvard. Characteristic for it is the separation of the data line from the line, after which orders are passed (instructions). More complexity allows you to speed up the operation of the microcomputer. This structure is used e.g.. in Mikrochip microcontrollers.

Let's think about it, which affects the speed of the microcomputer? The number of operations performed within a certain period of time depends directly on the frequency of the clock signal CLK. This signal forces subsequent operations performed by the microprocessor, and consequently by a microcomputer. However, this frequency cannot be increased indefinitely. The only limitation is the microprocessor itself. As a real logic it can work properly up to a certain frequency. The maximum operating frequency of the microprocessor is an important parameter, even on its housing. Memory access times may constitute another limitation in the maximum speed of reading and writing information.

The amount of information sent also depends on the number of data lines. The more lines of data, the more information can be sent in one operation. Eight lines allow the 1st byte to stop. Sixteen lines allow two bytes to stop, so the speed doubles. Internal data processing is also performed on I6-bit cows.