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Diffstat (limited to 'Documentation/i2c/busses/i2c-parport')
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diff --git a/Documentation/i2c/busses/i2c-parport b/Documentation/i2c/busses/i2c-parport new file mode 100644 index 0000000..9f1d008 --- /dev/null +++ b/Documentation/i2c/busses/i2c-parport @@ -0,0 +1,154 @@ +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: + * Philips adapter + * home brew teletext adapter + * Velleman K8000 adapter + * ELV adapter + * Analog Devices evaluation boards (ADM1025, ADM1030, ADM1031, ADM1032) + +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. + + +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/ |
