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C156-E097-01EN 7 - 33
Figure 7.14 Data transfer rate in synchronous mode
7.5.8 STATUS phase
In a STATUS phase, the TARG requests to transfer status information from the TARG to the
INIT. The TARG keeps the C/D and I/O signals true and the MSG signal false during
REQ/ACK handshaking in this phase.
7.5.9 MESSAGE phase
The MESSAGE phase is divided into MESSAGE IN and MESSAGE OUT phases depending on
the direction of message information transfer. In either phase, more than one message can be
transferred. The first byte transferred in a MESSAGE phase must be a single-byte message or
the first byte of a multiple-byte message. If the message consists of more than one byte, all bytes
must be transferred in a single MESSAGE phase. For details of message types and their
operation, see Chapter 5.
(1) MESSAGE IN phase
In a MESSAGE IN phase, the TARG requests to transfer message information from the TARG
to the INIT. The TARG keeps the C/D, I/O, and MSG signals true during REQ/ACK
handshaking in this phase.
(2) MESSAGE OUT phase
In a MESSAGE OUT phase, the TARG requests to transfer message information from the INIT
to the TARG. The TARG keeps the C/D and MSG signals true and I/O signal false during
REQ/ACK handshaking in this phase.
The TARG executes this phase in response to the ATTENTION condition (described in
Subsection 7.6.1) created by the INIT, and must remain in the MESSAGE OUT phase.