Data Bus Analysis Setup Menu

Note:  For LA16, click the “Next Page” button at the bottom of the screen to see and set up the remaining 8 channels

 

Bus Type – Parallel/Serial

Busses may be classified as either parallel or serial depending upon the number of bits transferred on each clock cycle. Serial busses transfer one bit per clock cycle. Parallel busses transfer multiple bits (on multiple wires) per clock cycle. The two Bus Type parameter boxes should be set first, since some of the other menu options will change depending upon the type of bus specified. For additional detail, see Parallel Busses or Serial Busses.

Bus Type – Asynchronous/Synchronous/Timed

Busses may be classified as either Asynchronous, Synchronous, or Timed depending on how the bus timing is to be determined. Asynchronous busses are inherently clocked by a change in the state of the data channels. Synchronous busses are clocked by one or more clock signals which are supplied on one or more input channels. Timed busses are clocked by specifying appropriate delays from a strobe or enable event. The two Bus Type parameter boxes should be set first, since some of the other menu options will change depending upon the type of bus specified. For additional detail, see Asynchronous Busses, Synchronous Busses, or Timed Busses.

Bit or Word Count and Order

For Serial busses, the Width parameter specifies the number of bits (up to 32) which are to be concatenated to form a data word. The Bit Order parameter will specify the order in which these bits will arrive (Most Significant First or Least Significant First), and the Postamble Bits parameter will specify how many bits follow the data word but are not part of the data word (such as parity bits, stop bits, etc.) For Parallel busses, the Burst length specifies the number of parallel transfers (up to four) which are to be concatenated to form a single data word and the burst order specifies the order in which the data word should be assembled. For additional detail, see Parallel Busses or Serial Busses.

Bus Timing Parameters – Asynchronous or Synchronous busses

For Asynchronous or Synchronous busses the noise filter specifies how long the data channels (for Asynchronous) or clock channels (for Synchronous) must remain stable following a transition before a bus clock is registered. This setting can be used to avoid generating false bus clocks due to skew or ringing. The Max Burst Duration / Max Word Duration setting is used to determine when a bus should be considered idle by the Reset On Idle option. This setting is also used to determine the size of the virtual window that must be analyzed in order to insure that all data inside the visible window is properly presented when the visible window is panned or zoomed. For additional detail, see Asynchronous Busses or Synchronous Busses.

Bus Timing Parameters – Timed busses

For Timed busses, the Delay From Strobe setting is used to determine when the first bus clock should be registered following the Strobe condition. The Clock Period setting is used to determine the timing of any serial or burst transfer clocks which may follow the first clock. For additional detail, see Timed Busses.

Data Specifications

For parallel busses, up to eight data channels can be specified. The channel specified as Data Bit 0 (or Data Bit BAR 0) will be the least significant bit, which must be defined. Data Bit (BAR) 1 will be the next least significant, and so forth. Any data bits specified using the Data Bit BAR selection will be logically inverted (0 Volts = one). For Serial busses, either a single Data or Data Bar channel can be specified, or both data and data-bar can be simultaneously defined on separate channels. If both Data and Data-Bar are defined, an invalid transfer will be logged unless the Data and Data-Bar channels are in opposite states when the bus clock occurs. An exception to this rule is allowed for the Asynchronous Serial case. For this special case, clocks where Data=Data-Bar will be ignored, and only periods where the two channels are in opposite data states will be registered as serial bit transfers. The bus data can be displayed as Hexadecimal data, Decimal data, or Ascii data depending upon the Bus Data setting. For additional detail, see Parallel Busses or Serial Busses.

Enable/Reset

The Enable/Reset column can be used to specify which data channels should be used to designate whether the bus is enabled or to designate when burst or serial transfers should be reset to the front of their sequence. Enable conditions are specified as states (such as On Low, or On High). Burst or Serial transfers will always be reset upon exit from a bus disabled state. Reset conditions are specified as events (such as On Rising or On Idle). For Reset On Edge conditions, state conditions on other channels can be used to indicate whether an edge should be acknowledged or ignored (such as Reset on Chan1 Rising When Chan3 is Low). For bus specifications that do not require multiple clocks, (and therefore do not need a reset) the Always Enabled option is allowed. For additional detail, see Asynchronous Busses, Synchronous Busses, or Timed Busses.

Clocks/Strobes

Clock channels (for Synchronous busses) or Strobe channels (for Timed busses) must be specified unless the Asynchronous bus type is selected. If multiple channels are specified, a clock or strobe will be registered on any of the specified edges. Clock or Strobe channels can be (but need not be) the same channels used for other purposes such as data or enable channels. For additional detail, see Synchronous Busses, or Timed Busses.

Visibility

The visibility check box indicates whether or not data collected on the given channel will be displayed on the screen. Visibility can be turned on or off for any channel at any time without affecting the acquired data or the bus analysis. The bus analysis is disabled if the bus visibility box is not checked. If the bus analysis is aborted due to an inconsistency in the bus definition, the bus visibility box will be automatically unchecked, and must be reselected once the bus definition has been corrected. For convenience, access to the channel visibility selections is provided on both the Bus Analysis Setup menu and the Data Acquisition Setup menu.

Signal Names

The signal name boxes can be used to specify the name that will be associated with the given channel or the bus when the signals are printed or displayed on the screen. Signal names can be changed for the bus or for any channel at any time without affecting the acquired data or the bus analysis. For convenience, access to the channel signal name specification boxes is provided on both the Bus Analysis Setup menu and the Data Acquisition Setup menu.

Color Selections

The color selection boxes can be used to specify the display colors to be used for each channel, as well as the bus, background, and grid, when the results are printed or displayed on the screen. Color selections are used for display only, and have no effect on the acquired data or bus analysis. Colors may be changed by simply clicking on the colored box. For convenience, access to the channel color boxes is provided on both the Bus Analysis Setup menu and the Data Acquisition Setup menu.

Ok and Cancel

Clicking the OK button will close the Bus Analysis Setup menu, saving all changes. Clicking on the Cancel button will close the Bus Analysis Setup menu and return to the main screen ignoring any changes.

All Bus Analysis Setup parameters can be saved to a file for later retrieval. (See Saving and Loading files for assistance).