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1 Kernel driver i2c-parport
3 Author: Jean Delvare <khali@linux-fr.org>
5 This is a unified driver for several i2c-over-parallel-port adapters,
6 such as the ones made by Philips, Velleman or ELV. This driver is
7 meant as a replacement for the older, individual drivers:
8 * i2c-philips-par
9 * i2c-elv
10 * i2c-velleman
11 * video/i2c-parport (NOT the same as this one, dedicated to home brew
12 teletext adapters)
14 It currently supports the following devices:
15 * (type=0) Philips adapter
16 * (type=1) home brew teletext adapter
17 * (type=2) Velleman K8000 adapter
18 * (type=3) ELV adapter
19 * (type=4) Analog Devices ADM1032 evaluation board
20 * (type=5) Analog Devices evaluation boards: ADM1025, ADM1030, ADM1031
21 * (type=6) Barco LPT->DVI (K5800236) adapter
22 * (type=7) One For All JP1 parallel port adapter
24 These devices use different pinout configurations, so you have to tell
25 the driver what you have, using the type module parameter. There is no
26 way to autodetect the devices. Support for different pinout configurations
27 can be easily added when needed.
29 Earlier kernels defaulted to type=0 (Philips). But now, if the type
30 parameter is missing, the driver will simply fail to initialize.
32 SMBus alert support is available on adapters which have this line properly
33 connected to the parallel port's interrupt pin.
36 Building your own adapter
37 -------------------------
39 If you want to build you own i2c-over-parallel-port adapter, here is
40 a sample electronics schema (credits go to Sylvain Munaut):
42 Device PC
43 Side ___________________Vdd (+) Side
44 | | |
45 --- --- ---
46 | | | | | |
47 |R| |R| |R|
48 | | | | | |
49 --- --- ---
50 | | |
51 | | /| |
52 SCL ----------x--------o |-----------x------------------- pin 2
53 | \| | |
54 | | |
55 | |\ | |
56 SDA ----------x----x---| o---x--------------------------- pin 13
57 | |/ |
58 | |
59 | /| |
60 ---------o |----------------x-------------- pin 3
61 \| | |
62 | |
63 --- ---
64 | | | |
65 |R| |R|
66 | | | |
67 --- ---
68 | |
69 ### ###
70 GND GND
72 Remarks:
73 - This is the exact pinout and electronics used on the Analog Devices
74 evaluation boards.
75 /|
76 - All inverters -o |- must be 74HC05, they must be open collector output.
77 \|
78 - All resitors are 10k.
79 - Pins 18-25 of the parallel port connected to GND.
80 - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
81 The ADM1032 evaluation board uses D4-D7. Beware that the amount of
82 current you can draw from the parallel port is limited. Also note that
83 all connected lines MUST BE driven at the same state, else you'll short
84 circuit the output buffers! So plugging the I2C adapter after loading
85 the i2c-parport module might be a good safety since data line state
86 prior to init may be unknown.
87 - This is 5V!
88 - Obviously you cannot read SCL (so it's not really standard-compliant).
89 Pretty easy to add, just copy the SDA part and use another input pin.
90 That would give (ELV compatible pinout):
93 Device PC
94 Side ______________________________Vdd (+) Side
95 | | | |
96 --- --- --- ---
97 | | | | | | | |
98 |R| |R| |R| |R|
99 | | | | | | | |
100 --- --- --- ---
101 | | | |
102 | | |\ | |
103 SCL ----------x--------x--| o---x------------------------ pin 15
104 | | |/ |
105 | | |
106 | | /| |
107 | ---o |-------------x-------------- pin 2
108 | \| | |
109 | | |
110 | | |
111 | |\ | |
112 SDA ---------------x---x--| o--------x------------------- pin 10
113 | |/ |
114 | |
115 | /| |
116 ---o |------------------x--------- pin 3
117 \| | |
118 | |
119 --- ---
120 | | | |
121 |R| |R|
122 | | | |
123 --- ---
124 | |
125 ### ###
126 GND GND
129 If possible, you should use the same pinout configuration as existing
130 adapters do, so you won't even have to change the code.
133 Similar (but different) drivers
134 -------------------------------
136 This driver is NOT the same as the i2c-pport driver found in the i2c
137 package. The i2c-pport driver makes use of modern parallel port features so
138 that you don't need additional electronics. It has other restrictions
139 however, and was not ported to Linux 2.6 (yet).
141 This driver is also NOT the same as the i2c-pcf-epp driver found in the
142 lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
143 an I2C bus directly. Instead, it uses it to control an external I2C bus
144 master. That driver was not ported to Linux 2.6 (yet) either.
147 Legacy documentation for Velleman adapter
148 -----------------------------------------
150 Useful links:
151 Velleman http://www.velleman.be/
152 Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html
154 The project has lead to new libs for the Velleman K8000 and K8005:
155 LIBK8000 v1.99.1 and LIBK8005 v0.21
156 With these libs, you can control the K8000 interface card and the K8005
157 stepper motor card with the simple commands which are in the original
158 Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
159 many more, using /dev/velleman.
160 http://home.wanadoo.nl/hihihi/libk8000.htm
161 http://home.wanadoo.nl/hihihi/libk8005.htm
162 http://struyve.mine.nu:8080/index.php?block=k8000
163 http://sourceforge.net/projects/libk8005/
166 One For All JP1 parallel port adapter
167 -------------------------------------
169 The JP1 project revolves around a set of remote controls which expose
170 the I2C bus their internal configuration EEPROM lives on via a 6 pin
171 jumper in the battery compartment. More details can be found at:
173 http://www.hifi-remote.com/jp1/
175 Details of the simple parallel port hardware can be found at:
177 http://www.hifi-remote.com/jp1/hardware.shtml