Implementation of Nibble Mode communication using Parallel Port Device Driver.

1. Host signals ability to take data by making the Busy pin low.

2. Now peripheral or writer responds by placing First nibble. Writer Writes on Data line, on the other side Reader reads from Status line.

3. Before reading from Reader side Peripheral or writer signals valid nibble by Sending signal on one of the status line.

4. The Reader indicate to writer that it has received the lower nibble. And is is not ready to accept another nibble. This is done by sending signal on status line to indicate the writer.

5. Now repeate all these steps for second nibble…

RCS file: header.h,v
Working file: header.h
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implemented linux/ioport.h and asm/io.h
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date: 2014/11/03 08:52:22;  author: root;  state: Exp;
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RCS file: declaration.h,v
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date: 2014/11/03 08:52:22;  author: root;  state: Exp;
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RCS file: initilization.c,v
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Implemented check_region(), request_region() and release_region()
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RCS file: cleanup.c,v
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Implemented release_region
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Initial revision

RCS file: dev_open.c,v
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RCS file: dev_release.c,v
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Initial revision

RCS file: dev_write.c,v
Working file: dev_write.c
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Written LSB nibble and MSB nibble. Taken character from application and calaulated LSB and MSB
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RCS file: dev_read.c,v
Working file: dev_read.c
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Read the Nibbles and arranged to calculate the original character
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RCS file: file_op.h,v
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Performed different file operations
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Initial revision

Write synopsis:

ch2 = ch1 & 0x0f;

ch3 = ch1 & 0xf0;
ch3 = ch3 >> 4;

Read synopsis:

ch1 = ch1 << 1;
ch1 = ch1 >> 4;
ch1 = ch1 & 0x0f;

ch2 = ch2 << 1;
ch2 = ch2 & 0xf0;

Enjoy Implementing……