Datasheet
Vinculum-II Embedded Dual USB Host Controller IC
Version 1.7
Document No.: FT_000138 Clearance No.: FTDI#143
6.3.2 Full Duplex
In full duplex mode, the SPI slave sends data on MISO line at the same time as it receives data on MOSI.
During the command phase this data is always the slave status byte. For a write command, write data
can be streamed out of MOSI and status can be sent during each write phase from slave to master. As
long as the slave status indicates that it can receive more data, the master can continue to stream
further write bytes. Figure 6.5 is an example of this.
SS#
MOSI
MISO
8 bit CMD
STATUS
W0
W1
W2
STATUS
STATUS
STATUS
Figure 6.5 Full Duplex Data Master Write
When the master is performing a data read, the data and status both need to share the same pin (MISO).
In this case the master and slave will exchange command and status bytes, followed by the slave sending
its data. If the Master keeps SS# active the Slave will send a further status byte after the data followed
by another data byte. This continues until the Master indicates the end of the communications by raising
SS#. Figure 6.6 is an example of this.
SS#
MOSI
MISO
8 bit CMD
STATUS
R0
STATUS
R1
Figure 6.6 Full Duplex Data Master Read
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