+++ /dev/null
-Primitive parallel port is driver for i2c bus, which exploits
-features of modern bidirectional parallel ports.
-
-Bidirectional ports have particular bits connected in following way:
-
- |
- /-----| R
- --o| |-----|
- read \-----| /------- Out pin
- |/
- - -|\
- write V
- |
- ---
-
-
-It means when output is set to 1 we can read the port. Therefore
-we can use 2 pins of parallel port as SDA and SCL for i2c bus. It
-is not necessary to add any external - additional parts, we can
-read and write the same port simultaneously.
- I only use register base+2 so it is possible to use all
-8 data bits of parallel port for other applications (I have
-connected EEPROM and LCD display). I do not use bit Enable Bi-directional
- Port. The only disadvantage is we can only support 5V chips.
-
-Layout:
-
-Cannon 25 pin
-
-SDA - connect to pin 14 (Auto Linefeed)
-SCL - connect to pin 16 (Initialize Printer)
-GND - connect to pin 18-25
-+5V - use external supply (I use 5V from 3.5" floppy connector)
-
-no pullups requied
-
-Module parameters:
-
-base = 0xXXX
-XXX - 278 or 378
-
-That's all.
-
-Daniel Smolik
-marvin@sitour.cz