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3.1 TR122 Software Architecture

The hardware and software design of the TR122 is rooted in well accepted flexible,

layered design concepts. The functional stack of all elements in the instrument design and data

flow are shown in Figure 3.1 below.

Figure 3.1 TR122 Software Architecture And Data Flow

The instrument hardware is mostly defined by a design which is software loadable into

a large field programmable gate array (FPGA) on the main board. The binary image of this

hardware design is saved on disk in the host computer and loaded to the instrument when the

software is started, or more specifically when the instrument application programming interface

(API) library is loaded in memory. The FPGA hardware design contains functional blocks to

interface with the instrument electronics, sample memory, and the PCI interface. Where the

software addresses specific registers on the instrument hardware, these registers are located

within the FPGA hardware.

The PCI interface itself contains a popular PCI bridge from PLX Technologies. The

advantage of using this device is that the gate array itself can be soft loaded and even potentially

reloaded after the host system is running. This provides flexibility and the ability to apply future

updates and enhancements to the hardware without the need to return the instrument to the

factory. The PCI9056 also has support available for a number of operating systems, including

native kernel support in some popular operating systems such as Linux. Under Windows a

comprehensive set of drivers and API features takes a lot of the work out of commonly needed

operations from basic device access to direct memory address support. The TR122 software

distribution includes an installation information file which directs the installation wizard to

install the Windows WDM kernel level driver and the associated PLX API for the benefit of a

newly installed TR122 instrument. These driver and API files contain the code necessary to

work with the operating system and the bridge chip on the other side of the PCI bus. They are

provided by PLX Technologies for distribution with systems that use these bridge chips. When

working with the software at this level under any operating system it may be helpful to acquire a

PLX Technologies software development kit. Generally, because the instrument API is

DDC TR122 User Manual

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