Coolpix MC-EU1 Protocol

Here are some informations about the serial protocol used between the Coolpix and the MC-EU1 remote.
Speed is set to 19200 bauds

* Introduction
This protocol use 1 or 4 bytes "packets". 4 bytes packets are used to send command to the coolpix and receive information from it.
1 byte packet are used as acknowledge (0x86), not acknowledge (0x15), "attention packet" (0xFF). 
Each byte in these packet is divided in two part, bit 0-6 is the value on 7 bits and bit 7 is the odd parity bit (thanks Mark Roberts !)
Returned value by the coolpix (in the two or three? last byte) have 0x1C offset, and least signifiant byte is sent first, for example
the number of picture is :

nb picture = ((byte[2] & 0x7F) - 0x1C) + 100 * ((byte[3] & 0x7F) - 0x1C) 
byte[0] == 0x9B, byte[1] == 0x10

* Going to MC-EU1 protocol

Send                             	Receive				Informations

0x00

					0x15

0x1B,0x53,0x06,0x00,0x00,0x11,0x02,0x00,0x00,0x00,0x13,0x00		Standard SetSpeed to 19200 command packet

					0x06

0x1B,0x53,0x06,0x00,0x00,0x11,0x02,0x00,0x00,0x10,0x23,0x00		Go to MC-EU1 protocol packet, switch LCD ON

					0x06

At first connection after Coolpix has been powerup, first 0x00 don't work, coolpix respond 0xFF 0xFF then nothing
A second 0x00 do the job.

* Initialisations

Need more informations...

Send                             	Receive				Informations

0x9B, 0x85, 0x1C, 0x1C

					0x9B, 0x13, 0x1C, 0x1C		?

0x86

* Has camera power down ?

Send                             	Receive				Informations

0x9B, 0x08, 0x1C, 0x1C

					0x9B, 0x92, 0x7F, 0x7F		Coolpix is ON
					or
					0x9B, 0x19, 0x7F, 0x7F		Coolpix powerdown.

0x86

* Take a shoot :

Send                             	Receive				Informations

0x9B, 0x01, 0x1C, 0x1C							Half press the shutter button.

					0x86

0x9B, 0x01, 0x7F, 0x1C							Full press the shutter button, 
									take the picture
					0x86

0x9B, 0x01, 0x7F, 0x7F							Release the shutter button,
									usefull in bulb mode
									
					0x8F
					
0x9B, 0x01, 0x1C, 0x7F							Half press release (unlock shutter button).
			
					0x86
					
* Zoom IN

Send                             	Receive				Informations

0x9B, 0x02, 0x1C, 0x1C							"Press" the zoom in button

					0x86
					
0x9B, 0x02, 0x1C, 0x7F							"Release" the zoom in button

					0x86

* Zoom OUT

Send                             	Receive				Informations

0x9B, 0x02, 0x7F, 0x1C							"Press" the zoom out button

					0x86
					
0x9B, 0x02, 0x7F, 0x7F							"Release" the zoom out button

					0x86
					
* Next picture

Send                             	Receive				Informations

0x9B, 0x04, 0x1C, 0x1C							"Press" right

					0x86
					
0x9B, 0x04, 0x1C, 0x7F							"Release" right

					0x86

* Previous picture

Send                             	Receive				Informations

0x9B, 0x04, 0x7F, 0x1C							"Press" left

					0x86
					
0x9B, 0x04, 0x7F, 0x7F							"Release" left

					0x86
					
* Number of picture left

Send                             	Receive				Informations

0x9B, 0x07, 0x1C, 0x1C

					0x9B, 0x10, 0xXX, 0xYY		(0xXX & 0x7F) - 0x1C + 100 * ((0xYY & 0x7F) - 0x1C) 
												is the number of pictures left

0x86

* A-REC/M-Rec

Send                             	Receive				Informations

0x9B, 0x89, 0x1C, 0x1C

					0x9B, 0x91, 0x9D, 0x7F		for A Rec mode
					or
					0x9B, 0x91, 0x0D, 0x1C		for M Rec mode
					or
					0x9B, 0x91, 0x7F, 0x9D		for play mode
					
0x86
					
* Go back to standard protocol

Send                             	Receive				Informations

0x9B, 0x8A, 0x1C, 0x1C							LCD OFF
				
					0x86
					
* "Attention" packet 0xFF from coolpix

Coolpix send 0xFF in many cases :
- After initialisation in response to 0x00.
- When Coolpix self powerdown (powersave)
- When Coolpix is powerdown
- When a picture has been recorded
- When mode selector is operated (A-Rec, M-Rec, Play)

It's a good idea to send 0x9B, 0x08, 0x1C, 0x1C packet to check
if coolpix has powerdown when a 0xFF is received, else check the
picture number and current mode.

* Notes

- Camera send NAK (0x15) in response to bad command packet

- You may send any useful informations about this protocol to : vladimir.vyskocil@wanadoo.fr