原创尼康热靴协议-3

 2012-6-12 17:37  1721 7 7 分类: 消费电子

Payload

The number of payload bytes differs from command to command: How many bytes are exchanged is stated in the table for the header byes. The sender of the payload is determined by the bit 4 in the header byte. If this bit is set the camera is the sender, else the camera receives the data.

INIT_0 (0xA1)

This if the first frame after either the camera is switched on or the speedlight is detected by the camera. The camera issues the command 0xA1 and the flash responds by sending 17 bytes and the checksum (seed 1d). Although the data is known for the SB800 the meaning of the data is unknown. Below you find the data send by the SB800, byte 1 is send first.

Byte	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
dec	1	1	2	1	8	7	1	50	150	100	12	78	165	44	67	38	67
hex	0x01	0x01	0x02	0x01	0x08	0x07	0x01	0x32	0x96	0x64	0x0C	0x4E	0xA5	0x2C	0x43	0x26	0x43

INIT_1 (0xB1)

The second frame after power-on is transmitted from the camera to the speedlight. It consists of 9 bytes plus a checksum (seed 1). The content of the nine bytes depends on the camera. I suspect the camera to tell the flash about its capabilities, for example about FP synchronization and BL as this is shown on the display of the flash. The meaning of the data is unknown. Below you find the data send to the speedlight by various cameras. Byte 1 is send first.