1.8253
8253 1.1 Address
Counter 0 Address: 40H, the address counter 1: 41H, the address counter 2: 42H, the control port address: 43H
Circuit 8253 1.2
[With maps, post-supplement]
Wherein, CLK0, CLK1 and CLK2 are clock the contact 1.19318MHz. 3 0 work using the counter, the count value of 65536, a frequency of 18.206HZ, period 54.925493ms, OUT0 IRQ0 8259 is connected. Counter 2 connected speakers.
2.8255
8255 1.1 Address
PA Port Address: 60H, port PB Address: 61H, PC Port Address: 62H, control port address: 63H
Port PA is input, for reading a keyboard scan code
An output port PB, the control speaker (PBl)
The input port of the PC, read the system status and configuration
