Corelis  - CAS-1000-I2C

The CAS-1000-I2C is an advanced instrument used in the monitoring and testing of devices and systems incorporating one or more I2C buses. The CAS-1000-I2C can be used to monitor in real-time and log I2C bus traffic, generate traffic to exercise the bus and communicate to its components, program in-system EEPROMs, validate bus specification compliance, confirm protocol of bus traffic, and emulate I2C compatible devices that are not yet physically connected to the bus. The CAS-1000-I2C also includes a JTAG controller that, when used with Corelis optional ScanExpress software, can perform boundary-scan interconnect testing and in-system programming of flash memories and CPLDs.

Because of its rich feature set, reliability, portability and ease-of use, the CAS-1000-I2C can be used in a wide variety of applications, such as product development, troubleshooting, validation, system integration, production, and field testing.32-bit Windows 2000/XP host software included with the CAS-1000-I2C provides highly user-friendly GUI control/visibility of the CAS-1000-I2C, including set-up, options, traffic visibility screens, and test actions. For integrating the CAS-1000-I2C into a new or existing test environment, the API included with the CAS-1000-I2C can be used to operate the CAS-1000-I2C from third party software applications such as National Instruments’ LabWindows/CVI and LabView software.
 

Software

The major functions of this instrument include:

Monitor: Passively listens and records all target bus traffic to display state and timing records and store in files. Includes message filtering, symbolic translation, and event trigger. Bus signal and protocol conformance is continually evaluated with deviations flagged.  The monitor window is shown below.

CAS-1000 Bus Monitor Window

Emulator: Enables concurrent virtual devices programmed to interact with the bus in addition to those of the target. These can include a Master (capable of multi-master arbitration), and up to 32 slaves. The above monitor includes and tags this emulated traffic.

Tester: Interprets a script program file to control a go-no-go test sequence, including bus electrical/timing parametric measurements. This enables automatic target bus specification compliance and functionality validation. It is suitable for design/development as well as factory acceptance testing.  The test script window is shown below.

CAS-1000 Test Script Window

Debugger: A user interactive bus I/O access portal. This enables individual bus transfers for immediate target communications. Looping supports repeated I/O patterns to facilitate external signal observations. Besides generic writing and reading of data blocks, a growing library of known standard devices is included showing interactive screens tailored to the device’s organization (such as ADCs, DACs, flash memories, SMbus behavior, etc.).  The debugger window is shown below.

CAS-1000 Debugger Window

Programmer: Provides easy-to use high-speed in-system programming of I2C compatible serial EEPROMs.  Two programmer windows are shown below.

CAS-1000 Programmer Window

CAS-1000 Programmer Read Device Contents Window

One application of the CAS-1000-I2C is to rapidly validate compliance of a target bus with the specification. This is supported at the electrical, timing, as well as the signaling level. Another application is to passively monitor any I/O activity transpiring on a target bus. This includes the detection of errant protocol. All such logged information is time stamped for history reconstruction. A third application is the programmed interchange of messages with the target bus system, also recorded by the monitoring function. This method can serve to generally exercise the target bus. It also supports target code development with debug stand-ins for non-existent bus devices. Finally, a general user PC to I2C communications link provides quick and direct visibility/control of target devices. This is extended to user applications via the provided API. 

I2C Parameters Scope

Using the Parameters Scope tool, the CAS-1000-I2C can be utilized to quickly measure and return the basic electrical and I2C timing parameters of the target bus without setting up the advanced scripting functions of the Test tool. It can gather master specific and slave-specific parameters, such as signal timing characteristics, and also system-wide parameters, such as bus voltage, pull-up resistance, and capacitance. Each measurement is compared to maximum and minimum values loaded from a specification file and the resulting pass or fail status is shown with the measurement. The Parameters Scope provides the additional ability to display a graph of captured signal edge transition data and a trigger can be set to capture a particular I2C bus signal's rising or falling edge.

CAS-1000 Parameters Scope Window

One application of the CAS-1000-I2C is to rapidly validate compliance of a target bus with the specification. This is supported at the electrical, timing, as well as the signalling level. Another application is to passively monitor any I/O activity transpiring on a target bus. This includes the detection of errant protocol. All such logged information is time stamped for history reconstruction. A third application is the programmed interchange of messages with the target bus system, also recorded by the monitoring function. This method can serve to generally exercise the target bus. It also supports target code development with debug stand-ins for non-existent bus devices. Finally, a general user PC to I2C communications link provides quick and direct visibility/control of target devices. This is extended to user applications via the provided API.

SMBus Support

The System Management Bus, or SMBus, was defined by Intel® Corporation in 1995 and is based on the I2C bus architecture. It is used in personal computers and servers for low-speed system management communications.

SMBus is a two-wire interface through which simple system and power management related chips can communicate with the rest of the system. A system using SMBus as a control bus for these system and power management related tasks passes messages to and from devices by addressed transfers, enabling moderate transfer rates using minimal board resources. With System Management Bus, for example, a device can provide manufacturer information, tell the system what its model/part number is, save its state for a suspend event, report different types of errors, accept control parameters, and return its status. The SMBus may share the same host device and physical bus with standard I2C components. Intel originally conceived the SMBus as the communication bus to accommodate Smart Batteries and other system and power management components.

The CAS-1000 software features SMBus decoding for common SMBus devices. Ordinarily, the raw data of the I2C transactions between SMBus devices must be manually decoded into meaningful information. With the SMBus decoding feature, a specific device address can be associated with a text file containing decoding information which allows the I2C Exerciser software to do the interpretation automatically.

The CAS-1000 also supports SMBus PEC (Packet Error Checking) message generation

CAS-1000 Bus Monitor Window in SMBus Decoding Mode