Document Reference No.: FT_000247
V2-EVAL Vinculum II Evaluation Board Datasheet Version 2.0
Clearance No.: FTDI#148
IOPROG#
From board I/O
IORESET
IOBUS23
header pins
IOBUS21
FT_TXD
FT_RXD
FT_RTS
FT_CTS
FT_DSR
FT_DTR
FT_DCD
FT_RI#
FT4232H I/O
ADBUS0
ADBUS1
ADBUS2
ADBUS3
ADBUS4
ADBUS5
ADBUS6
ADBUS7
1B1
1B2
VNC2_UART_RX
1A
U4
4 PORT
MUX
To VNC2
Device
VNC2_CTS#
2B1
2B2
2A
3A
4A
UART
VNC2_RESET#
VNC2_PROG#
3B1
3B2
4B1
4B2
SELECT
SN74CBT3257D
DB_TXD
DB_RXD
BDBUS0
BDBUS1
BDBUS2
BDBUS3
DEBUG
BDBUS4
BDBUS5
BDBUS6
BDBUS7
DB_TX_ENABLE
CDBUS0
VNC2_UART_RXD
CDBUS1
CDBUS2
CDBUS3
UART
‘SNIFFER’
INTERFACE
CDBUS4
CDBUS5
CDBUS6
CDBUS7
MUX SELECT
FT VNC RESET
FT VNC PROG
DDBUS0
DDBUS1
DDBUS2
MUX
CONTROL
DDBUS3
DDBUS5
DDBUS6
DDBUS7
SN74LVC2G125
INPUT EN
IN
INPUT
VNC2_DEBUG
U5 -2 PORT
BUFFER
OUT
OUTPUT
OUTPUT EN
U6 -INVERTER
Figure 6.1: FT4232H Configuration
6.1
UART Interface
The FT4232H channel A, ADBUS I/O, pins are used for UART operation with the VNC2. The UART inputs
to the FT4232H are supplied directly from the VNC2 device pins, while the UART outputs from the
FT4232H, are passed to an external multiplexer. The multiplexer allows the UART interface to the VNC2
to be driven by either by the FT4232H device or by an external UART device, which is connected to the
V2-EVAL board via the various board I/O header pins. The multiplexer select pin is controlled by pin
DDBUS0 on the FT4232H, where a logic „0‟ on the select pin will force the FT4232H device to drive the
UART interface on the VNC2, while a logic „1‟ will allow IOBUS21 and IOBUS23 header pins on the board
to drive the UART.
Copyright © 2010 Future Technology Devices International Limited
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