lain::tNikonLens Class Reference

Control Nikon F-mount lenses from an Arduino. More...

#include <NikonLens.h>

Public Types
enum	tResultCode { Success , Timeout }
	Possible result codes for commands.

Public Member Functions
void	begin (u8 handshakePin_In, u8 handshakePin_Out)
	Initialize SPI for lens communication.
void	end ()
	Tear down, relinquish resources.
tResultCode	sendCommand (u8 cmd, u8 byteCountFromLens=0, u8 *bytesFromLens=nullptr, u8 byteCountToLens=0, u8 const *bytesToLens=nullptr)
	Send lens command and read/write data.

Detailed Description

Control Nikon F-mount lenses from an Arduino.

Nikon lenses use a modified version of SPI. See also:

• Protocol: https://web.archive.org/web/20230323004623/http://nikonhacker.com/wiki/Lens_Serial_Interface
• Pinout: https://web.archive.org/web/20230323004623/http://nikonhacker.com/wiki/F-Mount
• Arduino SPI: http://arduino.cc/en/Reference/SPI

Connections are as follows (with Arduino Uno pin numbers):

• SS (10) is unused.
• SCK (13) is connected directly to lens SCLK.
• MISO (12) is connected to the lens Data line, which must be pulled high.
• MOSI (11) drives the lens Data line through a transistor, open-collector.
  So: MOSI -> Base, Data -> Collector, GND -> Emitter
• handshakePin_In is connected directly to lens H/S
• handshakePin_Out drives lens H/S through a transistor, open-collector.

NOTE: The Nikon D5100 starts communication with the lens at 96kHz, then increases speed to 156kHz if the lens supports it. Because the Arduino runs at 16MHz and the maximum divider ratio for SPI is 128, the slowest we can run the bus is 125kHz.
If using this code with older lenses causes problems, it should be modified to use the AVR's System Clock Prescaler to drop the CPU frequency so you can achieve a slower SPI bus speed.
I haven't tested this, it may interfere with other Arduino features.

Member Function Documentation

begin()

void lain::tNikonLens::begin	(	u8	handshakePin_In,
		u8	handshakePin_Out
	)

Initialize SPI for lens communication.

See class description for connection information.

Parameters

[in]	handshakePin_In	Input pin for reading the H/S line.
[in]	handshakePin_Out	Output pin for pulling the H/S line low.

sendCommand()

tNikonLens::tResultCode lain::tNikonLens::sendCommand	(	u8	cmd,
		u8	byteCountFromLens = 0,
		u8 *	bytesFromLens = nullptr,
		u8	byteCountToLens = 0,
		u8 const *	bytesToLens = nullptr
	)

Send lens command and read/write data.

Sends command cmd to the lens.
If data is to be received, byteCountFromLens must be set to the number of bytes expected.
If data is to be sent, byteCountToLens must be set to the number of bytes to send.
Received data is placed in bytesFromLens, so it must be sized accordingly.
Likewise, data sent to the lens is sourced from bytesToLens.

Parameters

[in]	cmd	The command byte to send.
[in]	byteCountFromLens	Number of bytes to receive, or zero if not receiving.
[out]	bytesFromLens	Destination for received bytes, or null if not receiving.
[in]	byteCountToLens	Number of bytes to send, or zero if not sending.
[in]	bytesToLens	Source of bytes sent to lens, or null if not sending.

Returns

A result code indicating success, or the failure cause.

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The documentation for this class was generated from the following files:

• NikonLens.h
• NikonLens.cpp