parallel port
D0-D7 is the data cable, S0-S7 is a status line, but S0, S1, S2 are invisible (you can also see from the figure), the status line is used to read data, but S0 is different. It is a timeout flag, and other status lines are used to send data from Section 10-11-12-13-15 (which can be seen).
The meaning of the printer pin:
l S0: In EPP (Enhanced Serial Port) mode, this location 1 is in the timeout.
L S1: Useless (estimated is decorative).
L S2: Nothing in most cases.
L S3: Set 0. It is usually called NERROR or NFAULT if the printer occurs.
L S4: If the data is reached, it is set 1. We are usually called SELECT.
L S5: If there is no paper, it is set 1. It is usually called Paperend or PapeRempty or PERROR.
L S6: If the printer gets a byte of data, this location is 0, usually called NACK or NACKNOWLEDGE.
L S7: If the printer is busy, this location is 0, usually called busy.
Control line:
These lines are usually used to output, but sometimes they can be used. They occupy C0-C7 (as shown), but C4, C5, C6, C7 on the interface are not visible, and the port address they take up is 0x37a.
l C0: This pin is reserved. He sends command to read the data on the port (D0-D7). When the computer is started, this bit is set 1, usually called NSTROBE.
l C1: Reserved. You can get the next print line by sending a command to the printer. (LF)
l C2: Reset the printer and empty the data buffer. (Ninitialize)
l C3: Reserved. Set high level open data input. Start the computer to set 0. (NSELECTIN)
Ground:
The needle from G0-G7 is grounded, they are generally used to improve the circuit.
Parallel port connector signal
Parallel input / output address
In my portinterop.cs file, I use this DLL as follows.
Using system;
Using system.Runtime.InteropServices;
Public Class Portaccess, PUBLIC CLASS PORTACCESS
{
[DLLIMPORT ("INPOUT32.DLL", entrypoint = "out32")]
Public Static Extern void Output (int adress, int value);
[DLLIMPORT ("INPOUT32.DLL", entrypoint = "inp32")]
Public Static Extern Int Input (Int AdRess);
}
The Output function is transmitted to the port, and the input is the data from the port.
Such as:
Portaccess.input (888); / / read data from 888 (ie 0x378) port
Portaccess.output (888, 4) // output 4 from 888 port
