Nikon NPR Series Руководство по интерфейсу связи - Страница 6

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Nikon Communication Interface Manual

- BCC: consists of 1-byte characters.

BCC= (S MOD 40h) + 20h

"S" in above formulae is the lower one byte of the total sum from "Sender

code" to "ETX" (=before BCC). "BCC" can be any value between 20h and

5Fh

* Compare the BCC in the received data and the calculated value.

If they are the same, the communication was successfully done.

- EOT: Trailer; End of the communication

The "CR/LF" is added at the end.

EOT = 04h

CR = 0dh

LF = 0ah

5-2. Procedures

When instrument receives a block of data, BCC is checked and ACK is to be returned if the

block was successfully received. NAK is to be returned if an error is reported.

If a NAK is received by the instrument, then the last block is to be resent by the instrument,

however, the count of NAK is not checked by the instrument, therefore, it is

recommendable to stop sending data by external devices side in such a case in order to

avoid any trouble which may be triggered in the hardware.

No reply (ACK) is required to ACK/NAK.

・Receiving Success

<A>

Command/Data

Block-X

・Receiving Error

Command/Data

Block-X

(Resend the same block)

Command/Data

Block-X

(h = hex)

(END)

P6/34

<B>

ACK

NAK

ACK

Confidential