Chapter 3 - Setup step two: channels

Contents

 

The channel groups are defined under the Setup window’s Channels tab . The channel groups tell the GoLogic software how the probe inputs are connected to the device under test. This allows the TriggerForms to be created, and the captured signals to be displayed in the WaveForm, Numeric, and PlugIn windows. Therefore, the channel groups must be defined before the TriggerForms or data windows are used.


Window areas

 
Display type
The Channel Groups tab offers several display types so that the channel groups can be defined using any mode you prefer. The display mode is selected via the "Display" drop-down list box...


 

"Pods" window areas
The "Pods" display displays the channels to match the lead set connectors...

 
Active group tabs
Select the active group by clicking on a group tab. Each group's name is displayed on the left side of the tabs, the bit-count is displayed in the center section. and the channel definition is displayed in the right section.

The group tabs can be organized via drag-n-drop. Click and hold the left mouse button on a group's tab until it is "picked up". Move the mouse vertically and the green insertion line will move. Release the left mouse button when the insertion line is at the new position.

The tab area width can be resized if needed. Move the mouse over the right edge of the tab area and the cursor changes to the resize icon...

Click and drag the tab area width using the left mouse button. To use the default tab area width, click the right mouse button while the resize icon is visible.

Likewise, the tab name-section can be resized to accommodate longer names. Move the mouse over the right edge of the group name section. The cursor changes to the resize icon...

Click and drag the name area wider using the left mouse button. Click the right mouse button while the icon is visible to use the default width for the name area.
 
The group tabs can also be arranged using drag-n-drop methods...
First, click and hold the left mouse button over a group tab until it is "lifted"...
   
Once the tab is "lifted", move the mouse to the desired insertion point...
   
Finally, release the mouse button to drop the tab in its new location...
 
The Transition detectors tab is displayed when transitional timing is active. See the Transition detectors topic later for more details.
 
Pods

The pod area is where the channels are added and removed from the active channel group...


Adding channels

 

 
The above example uses all channels in pod A. The lines below the channels in pod B indicate other groups use those channels. These underlines are used to avoid placing the same channel in more than one group. The CA0 through CA3 channels are not used in any group.

Click the left mouse button on the numbers to add/remove channels in the active group. Dragging the mouse across the channel numbers adds/removes multiple channels.

Each channel is added as the group's most significant bit. Therefore, dragging from left-to-right in a pod area adds the channels in ascending bit-order. Dragging from right-to-left adds the channels in descending bit-order. The bit-order can be edited in the Bit-Order area described next.

 

Bit-order

Each group’s bit-order can be customized in the bit-order area. First, click and hold the left mouse button on a channel token…


Bit-order

 
 
Then move the mouse to drag the channel to a new location in the group…
 
Finally, release the mouse to drop the token in its new location…
 
Multiple channels can also be selected and moved. First, create a selection rectangle by starting the left mouse button inside the bit-order area but off the channels tokens...
 
Once the desired channels are selected, drag the tokens to a new location in the group...
 
Finally, release the left mouse button to drop the tokens in their new order...
 
Once channel tokens are selected in the bit-order area, the Delete key removes those channels from the group. The Escape key unselects all channels. Clicking outside the bit-order area also unselects all channels.
 
Activity indicators
The activity indicators are updated about every half-second. They are intended to expose channels which are stuck low or high. Each channel can be high, low, or changing...
 
 
The GoLogic hardware temporarily samples a tiny batch of 250 MHz normal timing data to determine each channel's state. If a channel's data is all zeros, then the low-indicator is displayed. If a channel's data is all ones, then the high-indicator is displayed. Otherwise, the changing indicator is displayed.
 
Transition detectors
When transitional timing is active, the transition detector group tab is displayed. This is where you select which channels detect transitions and cause transitional timing to store samples to memory.

If a channel is not used in any channel group, the GoLogic software assumes it is not connected and ignores any input signals. These unconnected channels are ignored at run-time, cannot trigger the GoLogic, and cannot detect transitions.

For active channels used in at least one channel group, you can either allow each channel to detect transitions or to ignore transitions...
 

 
When one or more enabled channels determines that an input signal has changed, the GoLogic stores the sample to memory. Only connected channels are stored. Disabled transition detectors still store data provided they are used in at least one channel group.
 
Add group button
The add group button inserts a new group tab at the top of the list. An unlimited number of groups can be added. The new group is empty (has no channels). The new group has a default name "groupX", where X is a number which automatically increments for each new group.


Creating
channel groups

 
New groups are automatically added to the WaveForm and Numeric window's display. However, they won't appear in the window until channels are added. Empty groups are not displayed in the data windows.
 
Delete group button
The delete group button removes the active group from the list. Select a group tab to make it active, then click this button to delete the group.
 
At least one group tab always exists in the channel groups area. If the only group which exists is deleted, it is given a default name "group1" and all channels are removed.
 
Deleted groups are automatically removed from the TriggerForms, WaveForm, and Numeric windows. The TriggerForms use the "anything" event as a placeholder for deleted groups.
 
"All groups" action list
Contains actions which affect all channel groups...
  • Delete all: removes all groups. However, one tab always exists in the window. Using this action leaves a single tab with zero channels and the default name "group1".
  • Delete empty: removes all groups that have no channels.
  • All groups use ascending bit-order: sorts all groups with the ascending bit-order.
  • All groups use descending bit-order: sorts all groups with the descending bit-order.
"This group" action list
Contains actions which affect only the active channel group...
  • Show active-low line: displays a line over a group’s name which emphasizes the signal's meaning. This is a common naming convention used in electronics. When a zero is present on the signal, then it is active.
  • Use inverted logic: interprets samples below the threshold voltage as one while samples above the threshold are zero. Standard logic displays values above the threshold voltage as one while samples below the threshold are zero. This option inverts each bit when the group is displayed in the WaveForm and Numeric windows.
  • Remove all channels: deletes all channels in the group.
  • Sort ascending: makes the smallest channel number the least significant bit and the largest channel number the most significant bit. Channel A00 is the smallest channel number in the GoLogic. The clock channels are the largest channel numbers.
  • Sort descending: makes the largest channel number the least significant bit and the smallest  channel number the most significant bit.
  • Reverse bit-order: makes the least significant bit the most significant bit and vice versa.

The "Use inverted logic" option is often confused with the "Show active-low line" option. The inverted-logic type is related to the threshold voltage while the active-low line simply describes the signal’s meaning. For example, a group named "memread" with a active-low line above the name implies the device is reading from memory when that signal is zero. The active-low line is simply painted above the name as a reminder. The name and the active-low line work together to describe the signal. If the device reads from memory when the "memread" signal is one, then the active-low line should not be used.


Inverted logic
vs. Active-low

 
Name edit
Each channel group can be given a meaningful name indicating the group’s purpose with this control. For example, channels connected to the address signals from a microprocessor might be given the name ‘address bus’.

Each group name can be up to 127 characters long. Using names less than 30 characters is recommended because long names may be truncated if they do not fit in an area.

The past 10 group names is listed in the control's drop down. Select previously used group names using the drop-down list button.

 
Channel edit
If you dislike the click-and-drag pod areas described above, a group’s channels can also be edited using the channel edit box.

A range of channels is defined using the dash character. For example…

All pod A channels are used in the above example. Channel A00 is the least significant bit in the group while channel A15 is the most significant bit.

 
Individual channels are added using the comma character…

In the previous example, all pod A channels are used plus channel B07. Channel A00 is the least significant bit in the group while channel B07 is the most significant bit.

 
The least significant bit is at the start of the text, while channels added to the end of the text are the most significant bits in the group. Entering the channel numbers in reverse order reverses the bit-order…

 
Color list
Select a color for each channel group with this list. The "more..." button allows you to define custom colors. When a color is selected from the list, the channel group's color is synchronized in all WaveForm and Numeric windows. Therefore, the color list in the Channel Groups tab is a nice way to globally define a group's color.

Be aware that colors can also be set independently in each WaveForm line or Numeric column without affecting the other windows. If all windows use the same color to display a channel group, then that color appears in the Channel Groups tab color list. If any WaveForm lines or Numeric columns display the channel group using two or more unique colors, then the default gray appears in the Channel Groups tab color list. The group's color-swatch is also hidden.

The 9 "basic" colors automatically adjust to the pale or dark background colors. The software uses pale versions of these colors when a dark background is used. Likewise, the software uses dark versions when a pale background is used. This feature is very convenient if you open projects file from someone using a different background color.

However, custom colors do NOT adjust to pale or dark background colors. Opening a project file with custom colors may require the channel group colors to be adjusted. Alternatively, you can change your background color to something more compatible with the custom group colors.

 
Threshold buttons
The threshold buttons define the threshold level for each pod. See the Threshold levels section at the end of this chapter for more details.
 
Symbol Table button
A symbol table can be loaded into each channel group. Symbol tables associate a symbolic name to a numeric value. See Appendix E - Symbol table file formats for more details on the supported file types.


Loading
symbol
tables

Click the "Symbol Table..." button to load a symbol table file into the channel group. Once loaded, the symbols can be displayed in place of numeric values in the WaveForm, Numeric, and PlugIn window. More importantly, the symbols can be used in the TriggerForms rather than entering numeric values.

 
"Spreadsheet" window areas
The "Spreadsheet" mode displays the channels as columns and rows so that you can view all channel groups at the same time...



The Bit-order area is identical for all channel display modes and is described earlier in this chapter.

 
Setup area
Click the left mouse button in the setup area to resize the columns and edit the channel group names, width, color, etc. Clicking the right-mouse button on a line allows you to cut, copy, paste, and delete channel groups. Clicking either mouse button on the column labels above the setup area allows you to select which columns are visible. The drag-n-drop icons on the left edge of the setup area allow you to arrange the lines in any order. Finally, the entire setup area can be resized by dragging the left mouse button over the right edge of the setup area.

The up, down, left, and right arrow keys navigate to any field in the setup area. The active setup field is outlined with a black rectangle. Press the "return" key to edit the active setup field, and press either "escape" or "return" to exit edit-mode.
 

Channel selection area
The channel selection area allows you to add and remove channels to each group.

Click the left mouse button to add/remove channels in each group. Dragging the mouse across the channel selection area adds/removes multiple channels.

Each channel is added as the group's most significant bit. Therefore, dragging from left-to-right adds the channels in ascending bit-order. Dragging from right-to-left adds the channels in descending bit-order. The bit-order can be edited in the Bit-Order area described earlier.
 

"Mictor" window areas
The "Mictor" mode displays a top-down view of the female Mictor connector on your device...



The tab area, edit controls, threshold buttons, and Bit-order area are identical to the "Pods" display described earlier in this chapter.

 
Channel selection area
The channel selection area allows you to add and remove channels to each group.

Click the left mouse button on the pins and channel numbers to add/remove channels in each group. Dragging the mouse across the channel selection area adds/removes multiple channels.

Each channel is added as the group's most significant bit. Therefore, dragging from top-to-bottom adds the channels in ascending bit-order. Dragging from bottom-to-top adds the channels in descending bit-order. The bit-order can be edited in the Bit-Order area described earlier.
 

Channels and color
 
Color-groups
Each 16-channel pod is divided into two distinct color-groups. Therefore, each pod’s upper 8 channels are quickly distinguished from the lower 8 channels. The plastic wire separator and the end-connector determine the color-group. For example, the lower 8 channels in pod B are yellow...


Channel colors

 
 
Normal channel colors
The wires in each color group use the eight resistor-code colors...
 
 
Clock channel colors
Only four clock channels exist per 32 normal channels. Therefore, the clock pods are not divided into color groups. The clock channel lead set wires and connectors are green.
 
Virtual channels
Channels which are physically unavailable to the attached GoLogic are called "virtual channels". Virtual channels use faded colors to indicate their status. Channel groups which contain one or more virtual channel cannot be used in the TriggerForms, but can be used by the WaveForm, Numeric, and PlugIn windows to view the trace data. Virtual channels allow trace data to be easily shared between customers with different GoLogic models.

Unavailable channels are normally hidden so that no virtual channels exist in the tab. For example, a GoLogic-36 only displays pods A and B which are always physically available. However, loading a project captured from a GoLogic-72 causes pods C and D to be displayed. All channels in these pods are physically unavailable to the GoLogic-36 hardware, so these virtual channels are displayed in faded colors. You can define channel groups on these channels to view the 72-channel data, but you cannot trigger on these channels. The threshold buttons, transition detectors, and activity indicators on virtual channels are also disabled.

 
Channel group rules
  • An unlimited number of channel groups can be defined. The first channel group cannot be deleted, so at least one group always exists.
  • Each channel group can contain from 1 to 64 channels (64-bit buses are supported).
  • Each channel group name can have up to 127 characters.
  • The channels can can use any bit-order within a group. For example, channel CA0 can be the most significant bit in a group while channel B15 can be the least significant bit.
  • Empty channel groups contain no channels. Empty channel groups cannot be used in the TriggerForms and are not displayed in the WaveForm, Numeric, or PlugIn windows. We recommend deleting empty channel groups.
  • Channels can be used in more than one channel group. However, we do not recommend this practice because it can cause confusion in the TriggerForms.
  • Groups containing virtual channels cannot be used in the TriggerForms, but can be used to view trace data.
 
Threshold levels
The threshold level determines how the input signal is interpreted. Input voltages less than the threshold are converted to ‘0’. Input voltages greater than the threshold are converted to ‘1’...


Thresholds

The threshold levels can be set between –4.90 volts and +5.27 volts. TTL circuits use a threshold voltage level of +1.58 volts. ECL circuits use a threshold voltage level of -1.35 volts.
 
Minimum voltage swing
The minimum high voltage level is about 300 millivolts above the threshold. The maximum low voltage level is about 300 millivolts below the threshold. Therefore, there is an indeterminate range of about 600 millivolts around the threshold voltage level...
 
The GoLogic can support a 600 millivolt swing if the input signal’s quality is adequate.
 
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