the UART, SPI, and FIFO interfaces make up what is
termed the combined interface.
There are currently six precompiled Vinculum
supervisory firmware versions:
• VDIF
• VMSC
• VDPS
• VCDC
• VDFC
Disk and FTDI interface
Music player
Disk, PC monitor, and slave port
Communication class device
Disk and file copier
• VDAP
Disk and peripherals
My VDIP2 is loaded
with VDAP, the general-purpose firmware loads
and supports USB devices
on USB ports 1 and 2 with
the exception of the USB
BOMS device, which is
only supported on USB
port 2. The VDAP
command monitor
communicates with the
monitor device using one
of the interfaces that make
up the combined interface.
The VNC1L’s
command monitor
operates in two modes.
Data mode is used to pass
information from the
command monitor directly
to another device on USB
port 1 or USB port 2. To
communicate with the
VNC1L’s command
interpreter, Command
Mode must be invoked.
The DATAACK# and
DATAREQ# pins (the #
means that the pin is active
low) are used to switch
between Data Mode and
Command Mode.
The VNC1L firmware
will start in Command
Mode. The DATAACK#
and DATAREQ# pins need
to be held logically high at
firmware start to assure
■ SCHEMATIC 1. Looks very
similar to an everyday USB-enabled microcontroller
circuit, doesn’t it? Well, it
is... sorta. However, we
don’t have to write a single
byte of supervisor code.
Several different FTDI-supplied, application-specific firmware images
can be loaded into the
VNC1L. All we need to do
is to integrate a PICinto this
picture.
18
December 2008