Echelon I/O Model Reference for Smart Transceivers and Neu Instrukcja Użytkownika Pobierz pdf (Strona 77)

I/O Model Reference 67

Neuron Chip

Smart Transceiver

Pass Token CMP_RESYNCWrite Data

Pass Token

CMP_ACK

RESYNC

Write Data

Master Has

Token

Slave Has

Token

MASTER

SLAVE

Figure 24. Handshake Protocol Sequence between Master and Slave

When in possession of the write token, the device (Neuron Chip, Smart

Transceiver, or a host processor) can transfer up to 255 bytes of data. The stream

of data bytes is preceded by the command and length bytes. The token holder

keeps possession of the token until all data bytes have been written, after which

the token is passed to the attached device.

The same process can now be repeated by the other side or, alternatively, the

token can be passed back without any data.

Resynchronization Procedure

The procedure shown in Table 24 through Table 28 on page 70 applies to

master/slave A and master/slave B configuration. The master initiates the

resynchronization with a RESYNC (0x5A) command, and the slave acknowledges

with an ACKSYNC (0x07) command. If the slave does not respond, the master

continues to send the RESYNC command until the slave responds correctly.

Table 24. Resynchronization

Step Master Slave Comment

1 (Owns Token)

2 Write RESYNC Master initiates resynchronization

(0x5A)

1 2 ... 72 73 74 75 76 77 78 79 80 81 82 ... 208 209

Brak uwag

Echelon I/O Model Reference for Smart Transceivers and Neu Instrukcja Użytkownika Strona 77