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1da177e4 LT |
1 | Kernel driver i2c-parport |
2 | ||
3 | Author: Jean Delvare <khali@linux-fr.org> | |
4 | ||
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) | |
13 | ||
14 | It currently supports the following devices: | |
e97b81dd MH |
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 | |
1da177e4 LT |
22 | |
23 | These devices use different pinout configurations, so you have to tell | |
24 | the driver what you have, using the type module parameter. There is no | |
25 | way to autodetect the devices. Support for different pinout configurations | |
26 | can be easily added when needed. | |
27 | ||
e97b81dd MH |
28 | Earlier kernels defaulted to type=0 (Philips). But now, if the type |
29 | parameter is missing, the driver will simply fail to initialize. | |
30 | ||
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31 | |
32 | Building your own adapter | |
33 | ------------------------- | |
34 | ||
35 | If you want to build you own i2c-over-parallel-port adapter, here is | |
36 | a sample electronics schema (credits go to Sylvain Munaut): | |
37 | ||
38 | Device PC | |
39 | Side ___________________Vdd (+) Side | |
40 | | | | | |
41 | --- --- --- | |
42 | | | | | | | | |
43 | |R| |R| |R| | |
44 | | | | | | | | |
45 | --- --- --- | |
46 | | | | | |
47 | | | /| | | |
48 | SCL ----------x--------o |-----------x------------------- pin 2 | |
49 | | \| | | | |
50 | | | | | |
51 | | |\ | | | |
52 | SDA ----------x----x---| o---x--------------------------- pin 13 | |
53 | | |/ | | |
54 | | | | |
55 | | /| | | |
56 | ---------o |----------------x-------------- pin 3 | |
57 | \| | | | |
58 | | | | |
59 | --- --- | |
60 | | | | | | |
61 | |R| |R| | |
62 | | | | | | |
63 | --- --- | |
64 | | | | |
65 | ### ### | |
66 | GND GND | |
67 | ||
68 | Remarks: | |
69 | - This is the exact pinout and electronics used on the Analog Devices | |
70 | evaluation boards. | |
71 | /| | |
72 | - All inverters -o |- must be 74HC05, they must be open collector output. | |
73 | \| | |
74 | - All resitors are 10k. | |
75 | - Pins 18-25 of the parallel port connected to GND. | |
76 | - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high. | |
77 | The ADM1032 evaluation board uses D4-D7. Beware that the amount of | |
78 | current you can draw from the parallel port is limited. Also note that | |
79 | all connected lines MUST BE driven at the same state, else you'll short | |
80 | circuit the output buffers! So plugging the I2C adapter after loading | |
81 | the i2c-parport module might be a good safety since data line state | |
82 | prior to init may be unknown. | |
83 | - This is 5V! | |
84 | - Obviously you cannot read SCL (so it's not really standard-compliant). | |
85 | Pretty easy to add, just copy the SDA part and use another input pin. | |
86 | That would give (ELV compatible pinout): | |
87 | ||
88 | ||
89 | Device PC | |
90 | Side ______________________________Vdd (+) Side | |
91 | | | | | | |
92 | --- --- --- --- | |
93 | | | | | | | | | | |
94 | |R| |R| |R| |R| | |
95 | | | | | | | | | | |
96 | --- --- --- --- | |
97 | | | | | | |
98 | | | |\ | | | |
99 | SCL ----------x--------x--| o---x------------------------ pin 15 | |
100 | | | |/ | | |
101 | | | | | |
102 | | | /| | | |
103 | | ---o |-------------x-------------- pin 2 | |
104 | | \| | | | |
105 | | | | | |
106 | | | | | |
107 | | |\ | | | |
108 | SDA ---------------x---x--| o--------x------------------- pin 10 | |
109 | | |/ | | |
110 | | | | |
111 | | /| | | |
112 | ---o |------------------x--------- pin 3 | |
113 | \| | | | |
114 | | | | |
115 | --- --- | |
116 | | | | | | |
117 | |R| |R| | |
118 | | | | | | |
119 | --- --- | |
120 | | | | |
121 | ### ### | |
122 | GND GND | |
123 | ||
124 | ||
125 | If possible, you should use the same pinout configuration as existing | |
126 | adapters do, so you won't even have to change the code. | |
127 | ||
128 | ||
129 | Similar (but different) drivers | |
130 | ------------------------------- | |
131 | ||
132 | This driver is NOT the same as the i2c-pport driver found in the i2c | |
133 | package. The i2c-pport driver makes use of modern parallel port features so | |
134 | that you don't need additional electronics. It has other restrictions | |
135 | however, and was not ported to Linux 2.6 (yet). | |
136 | ||
137 | This driver is also NOT the same as the i2c-pcf-epp driver found in the | |
138 | lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as | |
139 | an I2C bus directly. Instead, it uses it to control an external I2C bus | |
140 | master. That driver was not ported to Linux 2.6 (yet) either. | |
141 | ||
142 | ||
143 | Legacy documentation for Velleman adapter | |
144 | ----------------------------------------- | |
145 | ||
146 | Useful links: | |
147 | Velleman http://www.velleman.be/ | |
148 | Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html | |
149 | ||
150 | The project has lead to new libs for the Velleman K8000 and K8005: | |
151 | LIBK8000 v1.99.1 and LIBK8005 v0.21 | |
152 | With these libs, you can control the K8000 interface card and the K8005 | |
153 | stepper motor card with the simple commands which are in the original | |
154 | Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and | |
155 | many more, using /dev/velleman. | |
156 | http://home.wanadoo.nl/hihihi/libk8000.htm | |
157 | http://home.wanadoo.nl/hihihi/libk8005.htm | |
158 | http://struyve.mine.nu:8080/index.php?block=k8000 | |
159 | http://sourceforge.net/projects/libk8005/ |