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Commit de3d27fc authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Dmitry Torokhov
Browse files

Input: walkera0701 - convert documentation into ReST format 



This file require minimum adjustments to be a valid ReST file.
Do it, in order to be able to parse it with Sphinx.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 730518f2

Documentation/input/walkera0701.txt

+35 −16
Original line number Original line Diff line number Diff line 
===========================

Walkera WK-0701 transmitter

===========================





Walkera WK-0701 transmitter is supplied with a ready to fly Walkera

Walkera WK-0701 transmitter is supplied with a ready to fly Walkera

helicopters such as HM36, HM37, HM60. The walkera0701 module enables to use

helicopters such as HM36, HM37, HM60. The walkera0701 module enables to use
@@ -10,7 +13,8 @@ or use cogito: 
cg-clone http://zub.fei.tuke.sk/GIT/walkera0701-joystick

cg-clone http://zub.fei.tuke.sk/GIT/walkera0701-joystick









Connecting to PC:

Connecting to PC

================





At back side of transmitter S-video connector can be found. Modulation

At back side of transmitter S-video connector can be found. Modulation

pulses from processor to HF part can be found at pin 2 of this connector,

pulses from processor to HF part can be found at pin 2 of this connector,
@@ -19,7 +23,8 @@ modulation pulses to PC, signal pulses must be amplified. 




Cable: (walkera TX to parport)

Cable: (walkera TX to parport)





Walkera WK-0701 TX S-VIDEO connector:

Walkera WK-0701 TX S-VIDEO connector::



 (back side of TX)

 (back side of TX)

     __   __              S-video:                                  canon25

     __   __              S-video:                                  canon25

    /  |_|  \             pin 2 (signal)              NPN           parport

    /  |_|  \             pin 2 (signal)              NPN           parport
@@ -30,10 +35,10 @@ Walkera WK-0701 TX S-VIDEO connector: 
     -------        3 __________________________________|________________ 25 GND

     -------        3 __________________________________|________________ 25 GND

                                                          E

                                                          E







I use green LED and BC109 NPN transistor.

I use green LED and BC109 NPN transistor.





Software:

Software

========





Build kernel with walkera0701 module. Module walkera0701 need exclusive

Build kernel with walkera0701 module. Module walkera0701 need exclusive

access to parport, modules like lp must be unloaded before loading

access to parport, modules like lp must be unloaded before loading
@@ -44,7 +49,8 @@ be changed by TX "joystick", check output from /proc/interrupts. Value for 












Technical details:

Technical details

=================





Driver use interrupt from parport ACK input bit to measure pulse length

Driver use interrupt from parport ACK input bit to measure pulse length

using hrtimers.

using hrtimers.
@@ -53,17 +59,29 @@ Frame format: 
Based on walkera WK-0701 PCM Format description by Shaul Eizikovich.

Based on walkera WK-0701 PCM Format description by Shaul Eizikovich.

(downloaded from http://www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf)

(downloaded from http://www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf)





Signal pulses:

Signal pulses

-------------



::



                     (ANALOG)

                     (ANALOG)

      SYNC      BIN   OCT

      SYNC      BIN   OCT

    +---------+      +------+

    +---------+      +------+

    |         |      |      |

    |         |      |      |

  --+         +------+      +---

  --+         +------+      +---





Frame:

Frame

-----



::



 SYNC , BIN1, OCT1, BIN2, OCT2 ... BIN24, OCT24, BIN25, next frame SYNC ..

 SYNC , BIN1, OCT1, BIN2, OCT2 ... BIN24, OCT24, BIN25, next frame SYNC ..





pulse length:

pulse length

------------



::



   Binary values:		Analog octal values:

   Binary values:		Analog octal values:





   288 uS Binary 0		318 uS       000

   288 uS Binary 0		318 uS       000
@@ -80,7 +98,8 @@ pulse length: 
(Warning, pulses on ACK are inverted by transistor, irq is raised up on sync

(Warning, pulses on ACK are inverted by transistor, irq is raised up on sync

to bin change or octal value to bin change).

to bin change or octal value to bin change).





Binary data representations:

Binary data representations

---------------------------





One binary and octal value can be grouped to nibble. 24 nibbles + one binary

One binary and octal value can be grouped to nibble. 24 nibbles + one binary

values can be sampled between sync pulses.

values can be sampled between sync pulses.
@@ -100,10 +119,10 @@ binary value can be sampled. This bit and magic number is not used in 
software driver. Some details about this magic numbers can be found in

software driver. Some details about this magic numbers can be found in

Walkera_Wk-0701_PCM.pdf.

Walkera_Wk-0701_PCM.pdf.





Checksum calculation:

Checksum calculation

--------------------





Summary of octal values in nibbles must be same as octal value in checksum

Summary of octal values in nibbles must be same as octal value in checksum

nibble (only first 3 bits are used). Binary value for checksum nibble is

nibble (only first 3 bits are used). Binary value for checksum nibble is

calculated by sum of binary values in checked nibbles + sum of octal values

calculated by sum of binary values in checked nibbles + sum of octal values

in checked nibbles divided by 8. Only bit 0 of this sum is used.
 
in checked nibbles divided by 8. Only bit 0 of this sum is used.