VNC2-48L1B FTDI, VNC2-48L1B Datasheet - Page 46

• Manufacturer Part Number: VNC2-48L1B
• Description: CONTROLLER, USB, VINCULUM II, 48LQFP
• Manufacturer: FTDI

Specifications of VNC2-48L1B

• Usb Type: Host Controller
• Usb Version: 2.0
• Data Rate: 12Mbps
• No. Of Ports: 2
• Supply Voltage Range: 1.62V To 1.98V, 2.97V To 3.63V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case: RoHS Compliant

6.3.3 Half Duplex, 4 pin
In half duplex mode, the MOSI signal is shared for both Master to Slave and Slave to Master
communications. When using 4 pins, the MISO signal carries the status bits. The Master initiates data
write transfer, this by asserting SS# and then sending out a command byte. This has the same format as
that shown in Figure 6-7. The Slave sends status during this command phase and if this indicates that
the Slave can accept data the Master will follow this up with a byte of write data. If the status continues
to indicate that more data can be written, a whole stream of data can be written following one single
command. The operation completes when the Master raises SS# again. Figure 6-8 is an example of this.
Figure 6-8 Half Duplex Data Master Write
Data reads are similar, apart from the MOSI pin changing from Slave input to Slave output after the
command phase. Figure 6-9 is an example. In this diagram, the Master drives the command while the
Slave returns with status. Then the MOSI buffers are turned round and a stream of read data is sent from
the Slave to the Master on the MOSI signal.
Figure 6-9 Half Duplex Data Master Read
MOSI
MOSI
MISO
MISO
SS#
SS#
Master to Slave
Copyright © 2010 Future Technology Devices International Limited
8 bit CMD
8 bit CMD
STATUS
STATUS
VINCULUM-II EMBEDDED DUAL USB HOST CONTROLLER IC Datasheet
STATUS
STATUS
W0
R0
Slave to Master
STATUS
STATUS
W1
R1
Document No.: FT_000138
Clearance No.: FTDI#
STATUS
STATUS
W2
R2
Version -
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1.2
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