0001 =========================
0002 Kernel driver i2c-parport
0003 =========================
0004
0005 Author: Jean Delvare <jdelvare@suse.de>
0006
0007 This is a unified driver for several i2c-over-parallel-port adapters,
0008 such as the ones made by Philips, Velleman or ELV. This driver is
0009 meant as a replacement for the older, individual drivers:
0010
0011 * i2c-philips-par
0012 * i2c-elv
0013 * i2c-velleman
0014 * video/i2c-parport
0015 (NOT the same as this one, dedicated to home brew teletext adapters)
0016
0017 It currently supports the following devices:
0018
0019 * (type=0) Philips adapter
0020 * (type=1) home brew teletext adapter
0021 * (type=2) Velleman K8000 adapter
0022 * (type=3) ELV adapter
0023 * (type=4) Analog Devices ADM1032 evaluation board
0024 * (type=5) Analog Devices evaluation boards: ADM1025, ADM1030, ADM1031
0025 * (type=6) Barco LPT->DVI (K5800236) adapter
0026 * (type=7) One For All JP1 parallel port adapter
0027 * (type=8) VCT-jig
0028
0029 These devices use different pinout configurations, so you have to tell
0030 the driver what you have, using the type module parameter. There is no
0031 way to autodetect the devices. Support for different pinout configurations
0032 can be easily added when needed.
0033
0034 Earlier kernels defaulted to type=0 (Philips). But now, if the type
0035 parameter is missing, the driver will simply fail to initialize.
0036
0037 SMBus alert support is available on adapters which have this line properly
0038 connected to the parallel port's interrupt pin.
0039
0040
0041 Building your own adapter
0042 -------------------------
0043
0044 If you want to build you own i2c-over-parallel-port adapter, here is
0045 a sample electronics schema (credits go to Sylvain Munaut)::
0046
0047 Device PC
0048 Side ___________________Vdd (+) Side
0049 | | |
0050 --- --- ---
0051 | | | | | |
0052 |R| |R| |R|
0053 | | | | | |
0054 --- --- ---
0055 | | |
0056 | | /| |
0057 SCL ----------x--------o |-----------x------------------- pin 2
0058 | \| | |
0059 | | |
0060 | |\ | |
0061 SDA ----------x----x---| o---x--------------------------- pin 13
0062 | |/ |
0063 | |
0064 | /| |
0065 ---------o |----------------x-------------- pin 3
0066 \| | |
0067 | |
0068 --- ---
0069 | | | |
0070 |R| |R|
0071 | | | |
0072 --- ---
0073 | |
0074 ### ###
0075 GND GND
0076
0077 Remarks:
0078 - This is the exact pinout and electronics used on the Analog Devices
0079 evaluation boards.
0080 - All inverters::
0081
0082 /|
0083 -o |-
0084 \|
0085
0086 must be 74HC05, they must be open collector output.
0087 - All resitors are 10k.
0088 - Pins 18-25 of the parallel port connected to GND.
0089 - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
0090 The ADM1032 evaluation board uses D4-D7. Beware that the amount of
0091 current you can draw from the parallel port is limited. Also note that
0092 all connected lines MUST BE driven at the same state, else you'll short
0093 circuit the output buffers! So plugging the I2C adapter after loading
0094 the i2c-parport module might be a good safety since data line state
0095 prior to init may be unknown.
0096 - This is 5V!
0097 - Obviously you cannot read SCL (so it's not really standard-compliant).
0098 Pretty easy to add, just copy the SDA part and use another input pin.
0099 That would give (ELV compatible pinout)::
0100
0101
0102 Device PC
0103 Side ______________________________Vdd (+) Side
0104 | | | |
0105 --- --- --- ---
0106 | | | | | | | |
0107 |R| |R| |R| |R|
0108 | | | | | | | |
0109 --- --- --- ---
0110 | | | |
0111 | | |\ | |
0112 SCL ----------x--------x--| o---x------------------------ pin 15
0113 | | |/ |
0114 | | |
0115 | | /| |
0116 | ---o |-------------x-------------- pin 2
0117 | \| | |
0118 | | |
0119 | | |
0120 | |\ | |
0121 SDA ---------------x---x--| o--------x------------------- pin 10
0122 | |/ |
0123 | |
0124 | /| |
0125 ---o |------------------x--------- pin 3
0126 \| | |
0127 | |
0128 --- ---
0129 | | | |
0130 |R| |R|
0131 | | | |
0132 --- ---
0133 | |
0134 ### ###
0135 GND GND
0136
0137
0138 If possible, you should use the same pinout configuration as existing
0139 adapters do, so you won't even have to change the code.
0140
0141
0142 Similar (but different) drivers
0143 -------------------------------
0144
0145 This driver is NOT the same as the i2c-pport driver found in the i2c
0146 package. The i2c-pport driver makes use of modern parallel port features so
0147 that you don't need additional electronics. It has other restrictions
0148 however, and was not ported to Linux 2.6 (yet).
0149
0150 This driver is also NOT the same as the i2c-pcf-epp driver found in the
0151 lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
0152 an I2C bus directly. Instead, it uses it to control an external I2C bus
0153 master. That driver was not ported to Linux 2.6 (yet) either.
0154
0155
0156 Legacy documentation for Velleman adapter
0157 -----------------------------------------
0158
0159 Useful links:
0160
0161 - Velleman http://www.velleman.be/
0162 - Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html
0163
0164 The project has lead to new libs for the Velleman K8000 and K8005:
0165
0166 LIBK8000 v1.99.1 and LIBK8005 v0.21
0167
0168 With these libs, you can control the K8000 interface card and the K8005
0169 stepper motor card with the simple commands which are in the original
0170 Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
0171 many more, using /dev/velleman.
0172
0173 - http://home.wanadoo.nl/hihihi/libk8000.htm
0174 - http://home.wanadoo.nl/hihihi/libk8005.htm
0175 - http://struyve.mine.nu:8080/index.php?block=k8000
0176 - http://sourceforge.net/projects/libk8005/
0177
0178
0179 One For All JP1 parallel port adapter
0180 -------------------------------------
0181
0182 The JP1 project revolves around a set of remote controls which expose
0183 the I2C bus their internal configuration EEPROM lives on via a 6 pin
0184 jumper in the battery compartment. More details can be found at:
0185
0186 http://www.hifi-remote.com/jp1/
0187
0188 Details of the simple parallel port hardware can be found at:
0189
0190 http://www.hifi-remote.com/jp1/hardware.shtml
