Patent Publication Number: US-2010111155-A1

Title: Serial Decode Correlation And Navigation

Description:
BACKGROUND 
     Modern oscilloscopes do much more than measure voltage and time. Agilent Oscilloscopes were the first to include 8b/10b decoding and a protocol view of a serial bus, described in U.S. Ser. No. 10/799,139, “Display of Digital Interface Symbol Information from an Analog Signal”, assigned to Agilent Technologies. This technology brings the protocol decoding capability of a protocol analyzer or logic analyzer into an oscilloscope. By displaying protocol in a scope, users can see signal integrity causes of logic faults. When incorrect packets of data are received, is it because they were transmitted incorrectly or because the electrical system that carried the data changed it? 
     Different display formats are used to convey the different layers of information contained in the signal. The traditional analog display of the signal is typically the focal point on an oscilloscope. However, once the signal is decoded into 8b/10b symbols or packets of data, it is preferred that this information be displayed in a listing similar to a logic analyzer or protocol analyzer. Hence the Agilent oscilloscopes represent this data as follows with the analog signal displayed at top in voltage and time and a listing below showing the logical content of the entire signal acquisition. 
     The user must examine the analog signal and look at specific bits to understand the nature of signal integrity issues. Was there a power supply switching, activity on an adjacent line causing crosstalk, etc? However, to see which packet is at fault requires the user to examine a broad span of time. There needs to be a way to correlate the information in the listing below to the analog signal above. 
     SUMMARY 
     The present invention includes a unique marker that provides the correlation and navigation through the analog data. The blue line on the analog trace in the screen shot above is correlated to the blue selected line in the listing. This tells the user which packet or symbol is being displayed in the analog trace. The selected line in the listing (listing row that is blue) and the blue line on the trace above indicate which packet is selected for the purpose of showing details and packet data in the other tabs in the listing window. 
     In addition to correlation, navigation can occur from either display. 
     This type of marker is an innovative approach to correlating and navigating the disparate data types displayed on a modern oscilloscope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a screen of the interface according to the invention. 
         FIG. 2  shows a process flowchart according to the invention. 
         FIG. 3  shows a process flowchart for step  100 A shown in  FIG. 2 . 
         FIG. 4  shows a functional block diagram according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a screen of the interface according to the invention. 
       FIG. 2  shows a process flowchart according to the invention. In step  6 , a signal trace and decode window are displayed. In step  8 , the display is navigated by either decode window or signal trace. 
     When the display is navigated by decode window, in step  42 , the entry in the decode window is highlighted. In step  44 , the time associated with the highlighted entry is determined. In step  46 , the position of the marker in the waveform window is determined. In step  48 , the waveform is moved such that the associated time corresponds to the marker location. 
     When the display is navigated by signal trace, in step  10 , a visual marker is selected. The marker may be selected in the analog signal display. In step  12 , the marker is positioned to the point of interest in the signal display. In step  14 , it is determined which pixel in the signal the marker is on. In step  16 , the time associated with the pixel is determined. In step  18 , it is determined which tab is selected in the decode window. In step  20 , the data associated with the time is visually emphasized. In the illustrative example shown in  FIG. 1 , the decode window is shown just below the signal display. 
     In operation, if the focus of attention is the analog trace, the user can move the blue line and see the corresponding selected line in the listing move. If necessary, the listing will automatically scroll to display the selected listing row. If the user pulls the blue line off the grid to the left or right, the analog trace will automatically start shifting one packet or symbol at a time. This will also have the effect of scrolling the listing if necessary. If the focus of attention is the listing, the user can scroll the listing and select the desired row by clicking on it. When the user clicks on a row in the listing, the analog trace will shift to place the middle of the selected symbol or packet at the location of the blue line. 
       FIG. 3  shows a process flowchart for step  20  shown in  FIG. 2 . There are two illustrative tabs shown. The first tab is indirectly associated data while the second tab is for directly associated data. 
     For indirectly associated data, in step  22 , the representation associated with the time is obtained. If the index is a symbol then the symbol associated with the time is found (shown in step  22 A). If the index is a packet, the packet associated with the time is found (shown in step  22 B). In step  24 , the line number associated with the data entry is obtained (shown in steps  24 A and  24 B). In step  26 , it is determined whether the line number currently displayed corresponds to the time of interest. If no, then in step  28 , the listing is scrolled to show the corresponding line number. If yes, then in step  30 , a visual indicator is initiated. The visual indicator may be a change in the background color of the line, highlighting the entry, “blinking” the entry, etc. 
     For directly associated data, in step  32 , the packet associated with the time is obtained. In step  34 , data specific to the selected parameter is displayed. If the selected parameter is “details” then details about that specific packet are displayed (shown in step  32 A and  34 A). If the selected parameter is “payload”, the payload for the packet may be displayed in hexadecimal bytes (shown in steps  32 B and  34 B). 
     As an alternative, the user may customize the screen views that are displayed or add additional views. 
       FIG. 4  shows a functional block diagram according to the invention. An instrument  80 , e.g. an oscilloscope, includes a signal display  82  and a processor  84 . A selector  86  positioning a marker on the signal display. The selector  86  may be mouse, touchpen, knob, keyboard, or touchscreen. 
     The processor  84  includes a correlator  88 , memory  90 , visual indicator  92 , and additional processing functions  94 . The correlator  88  determines a location for a pixel in the signal display corresponding to a position of the marker. The correlator  88  then converts pixels to time. Memory  90  contains times associated with the pixel and the location. A visual indicator  92  highlights a tab in a decode window corresponding to the time and marker. 
     The signal display  82  includes a signal trace  82 A and the decode window  82 B. The signal display  82 A may also include a measurement of time.