V2-EVAL Datasheet, PDF (41/64 Pages) Future Technology Devices International Ltd. – Vinculum II Evaluation Board

Document Reference No.: FT_000247
V2-EVAL Vinculum II Evaluation Board Datasheet Version 2.0
Clearance No.: FTDI#148
6.2
Debug Interface – UART Mode
The FT4232H channel B I/O pins are used to control the debug interface on the VNC2 device. The
channel is used to allow the device debug pin to be connected to a software debugger environment
running on a PC. The single bit, bi-directional debug signal from VNC2 is converted into a UART style
interface, with separate transmit and receive signals via a 2-port buffer. The signal on the BDBUS0 pin
corresponds to the transmit data from the debug software, while BDBUS1 corresponds to the receive
output from the VNC2. Pin BDBUS7, DB_TX_ENABLE, on the FT4232H is used for controlling transmit
and receive operation on the 2 port buffer. When signal DB_TX_ENABLE is „1‟ then the signal
VNC2_DEBUG will drive the DB_RXD input to the FT4232H. Alternatively when DB_TX_ENABLE is „0‟ then
the FT4232H UART output DB_TXD will drive the VNC2_DEBUG signal.
6.3
UART ‘Spy’ Interface
Channel C on the FT4232H device is configured as a UART interface. The channel is used as a „data spy‟
to detect any data sent to the VNC2 UART interface. The detected data is passed to software running on
the PC for display. The feature is used for detecting and displaying UART data from external sources
which are connected to the VNC2 UART interface, via the board I/O headers.
6.4
Device Control – Bit Bang Mode
The I/O signals on FT4232H channel D are used for additional control functions on the board. Pin
DDBUS0 is used to control the channel select input on the multiplexer. A logic „0‟ on the multiplexer
select pin will force multiplexer input B1 to drive the multiplexer output A, while a logic „1‟ will force
multiplexer input B2 to drive the multiplexer output.
Pins DDBUS1 and DDBUS2 are used for controlling the PROG# and RESET# inputs on the VNC2 from the
software via the FT4232H. Both pins are passed to the onboard multiplexer. A logic „0‟ on the
multiplexer select input will allow the VNC2 PROG# and RESET# pins to be controlled by the FT4232H.
Table 6.1, summarises the V2-EVAL board settings based on the value of the multiplexer select pin.
Multiplexer Select Pin Status
(Set by FT4232H DDBUS0)
Board Configuration Status
VNC2 UART interface connected to FT4232H channel A.
0
VNC2 RESET# connected to FT4232H DDBUS1 output.
VNC2 PROG# connected to FT4232H DDBUS2 output.
VNC2 UART interface connected to header pins on V2-EVAL board.
1
VNC2 RESET# connected to prototyping area header pin 50.
VNC2 PROG# connected to prototyping area header pin 49.
Table 6.1: Multiplexer Configuration Settings
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