linux/Documentation/i2c/busses/i2c-parport
<<
>>
Prefs
   1Kernel driver i2c-parport
   2
   3Author: Jean Delvare <khali@linux-fr.org> 
   4
   5This is a unified driver for several i2c-over-parallel-port adapters,
   6such as the ones made by Philips, Velleman or ELV. This driver is
   7meant 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
  14It 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
  24These devices use different pinout configurations, so you have to tell
  25the driver what you have, using the type module parameter. There is no
  26way to autodetect the devices. Support for different pinout configurations
  27can be easily added when needed.
  28
  29Earlier kernels defaulted to type=0 (Philips).  But now, if the type
  30parameter is missing, the driver will simply fail to initialize.
  31
  32
  33Building your own adapter
  34-------------------------
  35
  36If you want to build you own i2c-over-parallel-port adapter, here is
  37a sample electronics schema (credits go to Sylvain Munaut):
  38
  39Device                                                      PC
  40Side          ___________________Vdd (+)                    Side
  41               |    |         |
  42              ---  ---       ---
  43              | |  | |       | |
  44              |R|  |R|       |R|
  45              | |  | |       | |
  46              ---  ---       ---
  47               |    |         |
  48               |    |    /|   |
  49SCL  ----------x--------o |-----------x-------------------  pin 2
  50                    |    \|   |       |
  51                    |         |       |
  52                    |   |\    |       |
  53SDA  ----------x----x---| o---x---------------------------  pin 13
  54               |        |/            |
  55               |                      |
  56               |         /|           |
  57               ---------o |----------------x--------------  pin 3
  58                         \|           |    |
  59                                      |    |
  60                                     ---  ---
  61                                     | |  | |
  62                                     |R|  |R|
  63                                     | |  | |
  64                                     ---  ---
  65                                      |    | 
  66                                     ###  ###
  67                                     GND  GND
  68        
  69Remarks:
  70 - This is the exact pinout and electronics used on the Analog Devices
  71   evaluation boards.
  72                   /|
  73 - All inverters -o |- must be 74HC05, they must be open collector output.
  74                   \|
  75 - All resitors are 10k.
  76 - Pins 18-25 of the parallel port connected to GND.
  77 - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
  78   The ADM1032 evaluation board uses D4-D7. Beware that the amount of
  79   current you can draw from the parallel port is limited. Also note that
  80   all connected lines MUST BE driven at the same state, else you'll short
  81   circuit the output buffers! So plugging the I2C adapter after loading
  82   the i2c-parport module might be a good safety since data line state
  83   prior to init may be unknown. 
  84 - This is 5V!
  85 - Obviously you cannot read SCL (so it's not really standard-compliant).
  86   Pretty easy to add, just copy the SDA part and use another input pin.
  87   That would give (ELV compatible pinout):
  88
  89
  90Device                                                      PC
  91Side          ______________________________Vdd (+)         Side
  92               |    |            |    |
  93              ---  ---          ---  ---
  94              | |  | |          | |  | |
  95              |R|  |R|          |R|  |R|
  96              | |  | |          | |  | |
  97              ---  ---          ---  ---
  98               |    |            |    |
  99               |    |      |\    |    |
 100SCL  ----------x--------x--| o---x------------------------  pin 15
 101                    |   |  |/         | 
 102                    |   |             |
 103                    |   |   /|        |
 104                    |   ---o |-------------x--------------  pin 2
 105                    |       \|        |    |
 106                    |                 |    |
 107                    |                 |    |
 108                    |      |\         |    |
 109SDA  ---------------x---x--| o--------x-------------------  pin 10
 110                        |  |/              |
 111                        |                  |
 112                        |   /|             |
 113                        ---o |------------------x---------  pin 3
 114                            \|             |    |
 115                                           |    |
 116                                          ---  ---
 117                                          | |  | |
 118                                          |R|  |R|
 119                                          | |  | |
 120                                          ---  ---
 121                                           |    | 
 122                                          ###  ###
 123                                          GND  GND
 124
 125
 126If possible, you should use the same pinout configuration as existing
 127adapters do, so you won't even have to change the code.
 128
 129
 130Similar (but different) drivers
 131-------------------------------
 132
 133This driver is NOT the same as the i2c-pport driver found in the i2c
 134package. The i2c-pport driver makes use of modern parallel port features so
 135that you don't need additional electronics. It has other restrictions
 136however, and was not ported to Linux 2.6 (yet).
 137
 138This driver is also NOT the same as the i2c-pcf-epp driver found in the
 139lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
 140an I2C bus directly. Instead, it uses it to control an external I2C bus
 141master. That driver was not ported to Linux 2.6 (yet) either.
 142
 143
 144Legacy documentation for Velleman adapter
 145-----------------------------------------
 146
 147Useful links:
 148Velleman                http://www.velleman.be/
 149Velleman K8000 Howto    http://howto.htlw16.ac.at/k8000-howto.html
 150
 151The project has lead to new libs for the Velleman K8000 and K8005:
 152  LIBK8000 v1.99.1 and LIBK8005 v0.21
 153With these libs, you can control the K8000 interface card and the K8005
 154stepper motor card with the simple commands which are in the original
 155Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
 156many more, using /dev/velleman.
 157  http://home.wanadoo.nl/hihihi/libk8000.htm
 158  http://home.wanadoo.nl/hihihi/libk8005.htm
 159  http://struyve.mine.nu:8080/index.php?block=k8000
 160  http://sourceforge.net/projects/libk8005/
 161
 162
 163One For All JP1 parallel port adapter
 164-------------------------------------
 165
 166The JP1 project revolves around a set of remote controls which expose
 167the I2C bus their internal configuration EEPROM lives on via a 6 pin
 168jumper in the battery compartment. More details can be found at:
 169
 170http://www.hifi-remote.com/jp1/
 171
 172Details of the simple parallel port hardware can be found at:
 173
 174http://www.hifi-remote.com/jp1/hardware.shtml
 175
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.