Ocean Optics NeoFox Engineering Note - Manual (Page 11)

NeoFox Communication Interfaces
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Driver Interface and Hardware Interface
Some developers may wish to access the NeoFox device at the USB driver level or the hardware level. To do
this, developers will need to combine the information from the serial interface description in this document with
information from the USB-UART bridge chip manufacturer, FTDI. The chip that is used on the NeoFox is the
FT232RQ.
Driver Interface
An example of an application that would use the driver interface level would be an application that needs to run
on Linux or Macintosh computers – systems for which a USB driver is already available from FTDI but support
for the NeoFox DLL is not.
Driver information is available from FTDI at the link below. This documentation will explain how to use
function calls to the USB driver to exercise the USB-UART bridge’s UART. In other words, it will explain how
to write bytes to the UART and read bytes from the UART. In this way, the developer can use the serial
interface information from this document to interact with the microcontroller.
The driver documentation is located here: http://www.ftdichip.com/Drivers/D2XX.htm .
Hardware Interface
An example of an application that would use the hardware interface level would be a system that uses an
embedded microcontroller’s USB “On the Go” host feature to host the NeoFox. In this case, the developer
would need to write custom USB drivers for his device. To do this, he would need to understand the way that
the NeoFox hardware communicates over USB – the hardware interface.
Hardware interface documentation is also available from FTDI. This documentation explains how USB
commands can be sent to the device to exercise the UART. Again, this information can be combined with
knowledge of the serial interface to produce a compete interface description of the device.
Unfortunately, the hardware interface information from FTDI is not publicly available. However, it can be
obtained from FTDI by entering into an NDA with them. To obtain the USB communication documentation,
send an email to
[email protected] .
One important note for developers who will interface directly with the USB layer is that in order to begin
interacting with the device, the first step in communications will be to set up the USB chip’s UART settings.
These settings must match the NeoFox processor’s UART settings. Specifically, the developer will need to set
the baud rate, parity, data bits, and stop bits. Information on how to set these settings is provided in the OEM
documentation from the chip vendor, FTDI. The processor’s settings are listed in a table in the
NeoFox Serial
Interface section of this document.
NeoFox Variable Reference Table
The following table lists all publicly exposed parameters and variables that are available to the developer.
Because the DLL interface and serial interface both operate on the same variable space, the information contains
information that is relevant to both.
The table information is organized as follows: