VNC1L-1A-TRAY FTDI, VNC1L-1A-TRAY Datasheet - Page 16

• Manufacturer Part Number: VNC1L-1A-TRAY
• Description: USB Interface IC USB Vinculum Host /Dev Ctrl IC LQFP-48
• Manufacturer: FTDI

Specifications of VNC1L-1A-TRAY

• Product Category: USB Interface IC
• Rohs: yes
• Operating Supply Voltage: 3.3 V
• Operating Supply Current: 25 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: LQFP-48
• Minimum Operating Temperature: - 40 C
• Factory Pack Quantity: 250

5.2 SPI Interface
When the data and control buses are configured in SPI mode, the interface operates as an SPI Slave. An
SPI master is required to provide the clock (SCLK) signal and set the chip select (CS) for the duration of
the transaction. The SPI interface is a polled 4-wire interface which can operate at speeds up to 12MHz
The SPI interface differs from most other implementations in that it uses a 13 clock sequence to transfer
a single byte of data. In addition to a „Start‟ state, the SPI master must send two setup bits which
indicate data direction and target address. The encoding of the setup bits is shown in Table 5.3. A single
data byte is transmitted in each SPI transaction, with the most significant bit transmitted first.
After each transaction VNC1L returns a single status bit. This indicates if a Data Write was successful or a
Data Read was valid.
Table 5.3 SPI Setup Bit Encoding
5.2.1 Signal Descriptions
Table 5.4 Data and Control Bus Signal Mode Options - SPI Interface
The VNC1L SPI interface uses 4 signal lines: SCLK, CS, SDI and SDO. The signals SDI, SDO and CS
are always clocked on the rising edge of the SCLK signal.
CS signal must be raised high for the duration of the entire transaction. For data transactions, the CS
must be released for at least one clock cycle after a transaction has completed. It is not necessary to
release CS between Status Read operations.
The „Start‟ state of SDI and CS high on the rising edge of SCLK initiates the transfer. The transfer finishes
after 13 clock cycles, and the next transfer starts when SDI is high during the rising edge of SCLK.
The following Figure 5.3 and Table 5.5 give details of the bus timing requirements.
Pin No.
31
32
33
34
Direction
(R/W)
1
1
0
0
Name
SCLK
SDO
SDI
CS
Copyright © 2009 Future Technology Devices International Limited
Address
Target
0
1
0
1
Output
Input
Input
Input
Type
Vinculum VNC1L Embedded USB Host Controller IC Datasheet Version 2.02
Description
SPI Clock input
SPI Serial Data Input
SPI Serial Data Output
SPI Chip Select Input
Operation
Data Read
Status Read
Data Write
N/A
Meaning
Retrieve byte from Transmit Buffer
Read SPI Interface Status
Add byte to Receive Buffer
N/A
Document Reference No.: FT_000030
Clearance No.: FTDI# 50
16