 |
 |
 |
BitScope Logic is a 12 channel mixed signal logic timing and protocol analysis application.
Logic uses the high speed data capture capabilities of BitScope to implement a powerful but easy to use multi-channel mixed signal serial logic protocol analyzer.
Logic supports the SPI, I2C and CAN protocols as well as standard serial and logic timing analysis. In addition, up to 4 analog channels may be captured at the same time.
Features and benefits include:
Logic is perfect for debugging and analyzing systems that use serial logic, especially in a mixed signal context.
Most logic analyzers cannot even see analog waveforms but Logic captures both simultaneously to analyze and display mixed signal waveforms associated with serial or parallel logic in the system under test.
An important benefit of BitScope Logic is built-in packet decoding and inspection.
This means that in addition to displaying the logic timing and analog waveforms themselves Logic can decode and display the protocols encoded on those waveforms. For example here is RS-232:
RS-232 is a simple protocol for which packet inspection is little more than decoding and displaying each transmitted byte. However other protocols such as CAN (shown next) or I2C are rather more complex and can require more sophisticated analysis to diagnose faults.
Still others such as SPI (shown below) are even more generic in how they may be used and often make use of other logic signals beyond just the clock and/or serial data.
In all these cases the key diagnostic feature of Logic is Deep Packet Inspection.
This means that unlike an ordinary protocol receiver, Logic exposes each fragment of each packet for precise analysis on the timing display and in the optional packet list (on the right).
The example shown here lists fragments from both an SPI and I2C bus (from the same system) where each packet fragment is displayed in the order it was captured.
Other logic events may be interleaved with protocol fragments if required (in this example, an SPI ADC related SYNC signal) and any channel may be selectively disabled if not needed.
This makes diagnosing system faults at the hardware level much easier because it is possible to see at precisely which point in a protocol sequence a problem occured.
Of course knowing when a fault occurs is only half the story.
What one really needs to know is why it occurred at all.
This is where Logic can leverage the power of BitScope to capture one or more analog signals concurrently with logic.
Using analog channels to view some of the logic signals it can be easy to see the consequences of an underlying hardware fault which may be causing subtle errors in a digital system.
For example, ground bounce or an otherwise undetected noise issue may be affecting the reliability of a serial link, or perhaps a CAN or I2C device is not releasing from the bus at precisely the right time.
Whatever the problem, without deep packet inspection and mixed signal analysis it can be very hard to work out the underlying cause of an intermittent system fault.
Of course if more powerful analog signal analysis is required Logic is designed to work with other BitScope applications such as BitScope DSO or Meter, in some cases even allowing both applications to run with the one BitScope at the same time.
BitScope Logic is easy to use. Just point, click, zoom or drag with a mouse.
Capture controls are on screen and keyboard short-cuts are available for common operations.
Clicking any button activates its default action and right-clicking usually pops up an option menu.
The blue and orange buttons at the bottom of the application select capture duration and sample rate. Pre-trigger (data to capture before the trigger) may also be set and the capture armed.
Directly above the main controls are the cursor values (identified by a pair of triangles).
They report selected MARK (green) & POINT (red) timing values.
To the right are period and frequency values (between the cursors).
As with other BitScope applications, the cursors are the primary measurement tool. Cursors may be manually moved or automatically located based on timing edges, clocks, protocol packets and other things but they always report relevant timing between events in the capture buffer.
Above the cursors are the POD Connector Widget and Trace Navigator. The Connector Widget identifies the location of each channel as it appears on the BitScope front panel POD connector.
Channels light up when selected making it easy to connect up to the circuit correctly.
The Trace Navigator shows the entire capture buffer in overview and which part of the buffer is displayed.
The Navigator may be moved manually or automatically (depends on usage) but it always identifies which part of the entire capture is currently shown for analysis.
Built-in help is available at the click of a button and a full manual is installed with the software.
Logic deploys two concurrent protocol decoders.
The means that Logic can decode and display at least two protocol channels at once where each channel is configured via a control panel (e.g shown here on the right for SPI).
Each decoder takes control of 4 adjacent inputs where each input may particpate in the protocol or remain as raw logic.
Some decoders can work on all four inputs at once (e.g. CAN or UART which require only a single logic channel) but others (e.g. SPI or I2C) support fewer than 4 channels as they need more than one input per (protocol) channel.
In any case, inputs that are not required for protocol decoding may be used as general logic inputs or as additional protocol channels (e.g. for SPI as additional chip select signals). Trigger conditions may be established for cross-triggers between different protocol groups and analog channels.
Logic is included with all new BitScopes and is compatible with some older models.
Like most other BitScope software, Logic is cross-platform compatible with Windows 8 or 7 as as well most popular Linux distributions such as Debian, Ubuntu, Fedora and RedHat.