Echelon FT 3150 Smart Transceiver - Manual (Page 62)

Chapter 3 - Input/Output Interfaces
56 FT 3120 / FT 3150 Smart Transceiver Data Book
Read (length)
Write (data_0) // master begins data transfer to slave
Read (data_0)
. .
. .
. .
Write (data_n) // last byte of data to be transferred
Read (data_n)
Write EOM // end of data transfer (EOM=0x00)
Process EOM// exchange token
(Owns Token)
Slave writes buffer to master: Enter RD/_WR=1.
MASTER
SLAVE
(Owns Token)
Write XFER
// slave has data to write (XFER=0x01)
Read XFER
Write (length) // length=number of bytes of data
Read (length)
Write (data_0) // slave begins writing data to master
Read (data_0)
. .
. .
. .
Write (data_n) // last byte of data to be transferred
Read (data_n)
Write EOM // end of data transfer
Process EOM // exchange token
(Owns Token)
Master passes token to slave: Entry same as when master writes buffer to slave.
MASTER
SLAVE
(Owns Token)
Write NULL
// master has no data to send to slave
Read NULL // NULL=0x00
Write EOM // end of message (EOM=0x00)
Process EOM // exchange token
(Owns Token)
Slave passes token to master: Entry same as when slave writes buffer master.
MASTER
SLAVE
(Owns Token)
Write NULL
// slave has no data to send to the master
Read NULL // NULL=0x00
Write EOM // end of message (EOM=0x00)
Process EOM // exchange token
(Owns Token)