Performance indicators of the bus
1. Bus transmission cycle (bus cycle)
The time required for a bus operation (including application phase, addressing phase, transmission phase and end phase), usually consists of several bus clock cycles.
2. The bus clock cycle
is the clock cycle of the machine. The computer has a unified clock to control the various components of the entire computer, and the bus is also controlled by this clock. (In today's computers, the bus clock cycle may also be provided by the bridge)
3. Bus efficiency
The frequency of various operations on the bus is the reciprocal of the bus cycle.
If the bus cycle = N clock cycles, then the operating frequency of the bus = clock frequency / N.
In fact, it refers to sending data several times in one second.
4. The clock frequency of the bus
is the clock frequency of the machine, which is the reciprocal of the clock cycle.
If the clock period is T, the clock frequency is 1/T.
It actually refers to how many clock cycles there are in one second.
5. Bus width
Also known as bus bit width, it is the number of data bits that can be transmitted on the bus at the same time, usually referring to the number of data buses, such as 32 and called 32-bit (bit) bus.
6. Bus bandwidth
can be understood as the data transmission rate of the bus, that is, the number of bits of data that can be transmitted on the bus per unit time, usually measured by the number of bytes of information transmitted per second, and the unit is available bytes/second (B/s )express.
Bus bandwidth = bus operating frequency × bus width (bit/s) = bus operating frequency × (bus width/8) (B/s) = bus width/bus cycle (bit/s) = (bus width/8)/bus Cycle (B/s)
Note: The bus bandwidth refers to the highest transmission rate that the bus itself can achieve. To calculate the actual effective data transfer rate, divide the amount of data actually transferred by the elapsed time.
7. Bus multiplexing
Bus multiplexing means that a signal line transmits different information at different times. More information can be transmitted using fewer wires, saving space and cost.
8. The number of signal lines
The sum of the address bus, data bus and control bus is called the number of signal lines.