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- Kernel driver i2c-parport
- Author: Jean Delvare <khali@linux-fr.org>
- This is a unified driver for several i2c-over-parallel-port adapters,
- such as the ones made by Philips, Velleman or ELV. This driver is
- meant as a replacement for the older, individual drivers:
- * i2c-philips-par
- * i2c-elv
- * i2c-velleman
- * video/i2c-parport (NOT the same as this one, dedicated to home brew
- teletext adapters)
- It currently supports the following devices:
- * (type=0) Philips adapter
- * (type=1) home brew teletext adapter
- * (type=2) Velleman K8000 adapter
- * (type=3) ELV adapter
- * (type=4) Analog Devices ADM1032 evaluation board
- * (type=5) Analog Devices evaluation boards: ADM1025, ADM1030, ADM1031
- * (type=6) Barco LPT->DVI (K5800236) adapter
- These devices use different pinout configurations, so you have to tell
- the driver what you have, using the type module parameter. There is no
- way to autodetect the devices. Support for different pinout configurations
- can be easily added when needed.
- Earlier kernels defaulted to type=0 (Philips). But now, if the type
- parameter is missing, the driver will simply fail to initialize.
- Building your own adapter
- -------------------------
- If you want to build you own i2c-over-parallel-port adapter, here is
- a sample electronics schema (credits go to Sylvain Munaut):
- Device PC
- Side ___________________Vdd (+) Side
- | | |
- --- --- ---
- | | | | | |
- |R| |R| |R|
- | | | | | |
- --- --- ---
- | | |
- | | /| |
- SCL ----------x--------o |-----------x------------------- pin 2
- | \| | |
- | | |
- | |\ | |
- SDA ----------x----x---| o---x--------------------------- pin 13
- | |/ |
- | |
- | /| |
- ---------o |----------------x-------------- pin 3
- \| | |
- | |
- --- ---
- | | | |
- |R| |R|
- | | | |
- --- ---
- | |
- ### ###
- GND GND
-
- Remarks:
- - This is the exact pinout and electronics used on the Analog Devices
- evaluation boards.
- /|
- - All inverters -o |- must be 74HC05, they must be open collector output.
- \|
- - All resitors are 10k.
- - Pins 18-25 of the parallel port connected to GND.
- - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
- The ADM1032 evaluation board uses D4-D7. Beware that the amount of
- current you can draw from the parallel port is limited. Also note that
- all connected lines MUST BE driven at the same state, else you'll short
- circuit the output buffers! So plugging the I2C adapter after loading
- the i2c-parport module might be a good safety since data line state
- prior to init may be unknown.
- - This is 5V!
- - Obviously you cannot read SCL (so it's not really standard-compliant).
- Pretty easy to add, just copy the SDA part and use another input pin.
- That would give (ELV compatible pinout):
- Device PC
- Side ______________________________Vdd (+) Side
- | | | |
- --- --- --- ---
- | | | | | | | |
- |R| |R| |R| |R|
- | | | | | | | |
- --- --- --- ---
- | | | |
- | | |\ | |
- SCL ----------x--------x--| o---x------------------------ pin 15
- | | |/ |
- | | |
- | | /| |
- | ---o |-------------x-------------- pin 2
- | \| | |
- | | |
- | | |
- | |\ | |
- SDA ---------------x---x--| o--------x------------------- pin 10
- | |/ |
- | |
- | /| |
- ---o |------------------x--------- pin 3
- \| | |
- | |
- --- ---
- | | | |
- |R| |R|
- | | | |
- --- ---
- | |
- ### ###
- GND GND
- If possible, you should use the same pinout configuration as existing
- adapters do, so you won't even have to change the code.
- Similar (but different) drivers
- -------------------------------
- This driver is NOT the same as the i2c-pport driver found in the i2c
- package. The i2c-pport driver makes use of modern parallel port features so
- that you don't need additional electronics. It has other restrictions
- however, and was not ported to Linux 2.6 (yet).
- This driver is also NOT the same as the i2c-pcf-epp driver found in the
- lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
- an I2C bus directly. Instead, it uses it to control an external I2C bus
- master. That driver was not ported to Linux 2.6 (yet) either.
- Legacy documentation for Velleman adapter
- -----------------------------------------
- Useful links:
- Velleman http://www.velleman.be/
- Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html
- The project has lead to new libs for the Velleman K8000 and K8005:
- LIBK8000 v1.99.1 and LIBK8005 v0.21
- With these libs, you can control the K8000 interface card and the K8005
- stepper motor card with the simple commands which are in the original
- Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
- many more, using /dev/velleman.
- http://home.wanadoo.nl/hihihi/libk8000.htm
- http://home.wanadoo.nl/hihihi/libk8005.htm
- http://struyve.mine.nu:8080/index.php?block=k8000
- http://sourceforge.net/projects/libk8005/
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