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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:03 EST.

1	Kernel driver i2c-parport
2	
3	Author: Jean Delvare <jdelvare@suse.de>
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:
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
23	
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.
28	
29	Earlier kernels defaulted to type=0 (Philips).  But now, if the type
30	parameter is missing, the driver will simply fail to initialize.
31	
32	SMBus alert support is available on adapters which have this line properly
33	connected to the parallel port's interrupt pin.
34	
35	
36	Building your own adapter
37	-------------------------
38	
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):
41	
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
71	        
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):
91	
92	
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
127	
128	
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.
131	
132	
133	Similar (but different) drivers
134	-------------------------------
135	
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).
140	
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.
145	
146	
147	Legacy documentation for Velleman adapter
148	-----------------------------------------
149	
150	Useful links:
151	Velleman                http://www.velleman.be/
152	Velleman K8000 Howto    http://howto.htlw16.ac.at/k8000-howto.html
153	
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/
164	
165	
166	One For All JP1 parallel port adapter
167	-------------------------------------
168	
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:
172	
173	http://www.hifi-remote.com/jp1/
174	
175	Details of the simple parallel port hardware can be found at:
176	
177	http://www.hifi-remote.com/jp1/hardware.shtml
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