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@@ -1,3 +1,6 @@
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+===========================
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+Walkera WK-0701 transmitter
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+===========================
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Walkera WK-0701 transmitter is supplied with a ready to fly Walkera
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helicopters such as HM36, HM37, HM60. The walkera0701 module enables to use
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@@ -10,7 +13,8 @@ or use cogito:
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cg-clone http://zub.fei.tuke.sk/GIT/walkera0701-joystick
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-Connecting to PC:
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+Connecting to PC
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+================
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At back side of transmitter S-video connector can be found. Modulation
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pulses from processor to HF part can be found at pin 2 of this connector,
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@@ -19,7 +23,8 @@ modulation pulses to PC, signal pulses must be amplified.
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Cable: (walkera TX to parport)
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-Walkera WK-0701 TX S-VIDEO connector:
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+Walkera WK-0701 TX S-VIDEO connector::
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+
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(back side of TX)
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__ __ S-video: canon25
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/ |_| \ pin 2 (signal) NPN parport
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@@ -30,10 +35,10 @@ Walkera WK-0701 TX S-VIDEO connector:
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------- 3 __________________________________|________________ 25 GND
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E
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-
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I use green LED and BC109 NPN transistor.
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-Software:
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+Software
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+========
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Build kernel with walkera0701 module. Module walkera0701 need exclusive
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access to parport, modules like lp must be unloaded before loading
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@@ -44,7 +49,8 @@ be changed by TX "joystick", check output from /proc/interrupts. Value for
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-Technical details:
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+Technical details
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+=================
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Driver use interrupt from parport ACK input bit to measure pulse length
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using hrtimers.
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@@ -53,17 +59,29 @@ Frame format:
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Based on walkera WK-0701 PCM Format description by Shaul Eizikovich.
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(downloaded from http://www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf)
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-Signal pulses:
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- (ANALOG)
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- SYNC BIN OCT
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- +---------+ +------+
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- | | | |
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---+ +------+ +---
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+Signal pulses
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+-------------
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+
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+::
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+
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+ (ANALOG)
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+ SYNC BIN OCT
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+ +---------+ +------+
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+ | | | |
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+ --+ +------+ +---
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+
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+Frame
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+-----
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+
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+::
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-Frame:
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SYNC , BIN1, OCT1, BIN2, OCT2 ... BIN24, OCT24, BIN25, next frame SYNC ..
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-pulse length:
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+pulse length
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+------------
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+
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+::
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+
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Binary values: Analog octal values:
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288 uS Binary 0 318 uS 000
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@@ -80,7 +98,8 @@ pulse length:
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(Warning, pulses on ACK are inverted by transistor, irq is raised up on sync
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to bin change or octal value to bin change).
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-Binary data representations:
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+Binary data representations
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+---------------------------
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One binary and octal value can be grouped to nibble. 24 nibbles + one binary
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values can be sampled between sync pulses.
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@@ -100,10 +119,10 @@ binary value can be sampled. This bit and magic number is not used in
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software driver. Some details about this magic numbers can be found in
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Walkera_Wk-0701_PCM.pdf.
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-Checksum calculation:
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+Checksum calculation
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+--------------------
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Summary of octal values in nibbles must be same as octal value in checksum
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nibble (only first 3 bits are used). Binary value for checksum nibble is
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calculated by sum of binary values in checked nibbles + sum of octal values
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in checked nibbles divided by 8. Only bit 0 of this sum is used.
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-
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