并行端口

维基百科，自由的百科全书

康柏N150型笔记本电脑的打印机并行端口

并行端口是计算机上数据以并行方式传递的端口，也就是说至少应该有两条连接线用于传递数据。与只使用一根线传递数据（这里没有包括用于接地、控制等的连接线）的串行端口相比，并口在相同的数据传送速率下，并口可以更快地传输数据。所以在21世纪之前，在需要较大传输速度的地方，例如打印机，并口得到广泛使用。但是随着速度迅速提高，并口上导线之间数据同步成为一个很难处理的难题,导致并口在速度竞赛中逐渐被淘汰。目前USB等改进的串口逐渐代替了并口。

[编辑] 用途

印表機
Zip drive
影像掃描器
some early sound cards
some old Webcams
peripheral devices such as EPROM programmers, emulators

[编辑] Port addresses

Traditionally IBM PC systems have allocated their first three parallel ports according to the configuration in the table below.

埠號	中斷 #	Starting I/O	Ending I/O
`LPT1`	`IRQ 7`	`0x3bc`	`0x3bf`
`LPT2`	`IRQ 5`	`0x378`	`0x37f`
`LPT3`	`IRQ 5`	`0x278`	`0x27f`

If there is an unused LPTx slot, the port addresses of the others are moved up. (For example, if a port at 0x3bc does not exist, the port at 0x378 will then become LPT1.) The IRQ lines, however, remain fixed (therefore, 0x378 at LPT1 would use IRQ 7). The port addresses assigned to each LPTx slot can be determined by reading the BIOS Data Area (BDA) at 0000:0408.

Bit to Pin Mapping for the Standard Parallel Port (SPP):

Address	別名		MSB							LSB
		Bit:	7	6	5	4	3	2	1	0
`Base`	資料輸出	Pin:	9	8	7	6	5	4	3	2
`Base+1`	狀態輸入	Pin:	~11	10	12	13	15
`Base+2`	控制	Pin:					~17	16	~14	~1

~ indicates a hardware inversion of the bit.

[编辑] Pin definition

Pin No (D-Type 25)	Pin No (Centronics)	SPP Signal	Direction In/out	Register	Hardware Inverted
1	1	~Strobe	In/Out	Control	Yes
2	2	Data 0	Out	Data
3	3	Data 1	Out	Data
4	4	Data 2	Out	Data
5	5	Data 3	Out	Data
6	6	Data 4	Out	Data
7	7	Data 5	Out	Data
8	8	Data 6	Out	Data
9	9	Data 7	Out	Data
10	10	~Ack	In	Status
11	11	Busy	In	Status	Yes
12	12	Paper-Out / Paper-End	In	Status
13	13	Select	In	Status
14	14	~Auto-Linefeed	In/Out	Control	Yes
15	32	~Error / ~Fault	In	Status
16	31	Initialize	In/Out	Control
17	36	~Select-Printer / ~Select-In	In/Out	Control	Yes
18 - 25	19-30	Ground	Gnd