Tasks State

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The Tasks State block outputs the execution state of scheduled tasks to GPIO pins for visualization with an oscilloscope or logic analyzer.

When to use:

When to use:

• Debugging multitasking behavior with oscilloscope/logic analyzer
• Visualizing task preemption and execution order externally
• Measuring actual task execution time (pulse width on GPIO pin)
• Identifying unexpected task scheduling issues (jitter, missed deadlines)
• Demonstrating real-time scheduler behavior during development

When NOT to use:

• Sufficient GPIO pins not available (one pin per task monitored)
• No external measurement tools available (scope/logic analyzer)
• Software-only profiling sufficient (use MCU LOAD block instead)
• Pin toggling overhead unacceptable (minimal but non-zero)

Overview

The Tasks State block drives GPIO pins to indicate when tasks are executing. Each task in the model can be assigned a dedicated pin that reflects its execution state, enabling external observation of task scheduling behavior.

Block Dialog

Parameters

Pin Syntax

The TasksPin parameter accepts flexible GPIO pin specifications:

• Space-separated: A0 A1 A2 assigns pins A0, A1, A2 to the first three tasks
• Range notation: A[1:5] assigns pins A1 through A5 to the first five tasks
• Mixed notation: A0 B[2:4] C1 assigns A0, B2, B3, B4, C1 to tasks sequentially

Special value: -1 skips pin assignment for the corresponding task (no pin is affected for that task).

Pin Behavior

For each task, the corresponding pin is set:

• HIGH when:
  • The task is running, OR
  • The task execution is not finished but interrupted by a higher priority task
• LOW otherwise (task idle or completed)

The first pin in the list corresponds to the highest rate/priority task (fastest sample time). Press Ctrl+J in the model to show the task list.

Task-to-Pin Mapping

When you open the block dialog, it displays the current task list with assigned pins. Example from mask description:

Task List updated with last model build
D1 => 1 (ms) ->  pin A1
D2 => 2 (ms) ->  pin A2
D3 => 4 (ms) ->  pin A3
D4 => 4  {+1} (ms) ->  pin A4
D5 => 20 (ms) ->  pin A5

The block also lists available pins by port:

Available pins:
         A  [0   1   2   3   4   5   6   7   9  10  14  15]
         B  [0 : 15]
         C  [1   2   3   4  12  13  14  15]
         D  [0 : 15]
         E  [0 : 9]
         F  [0   1   2   3   4   5   8  12  13]
         G  [0   1   2   3   6   7   8   9  12  13  14  15]

(Available pins depend on the selected device and peripheral configuration.)

Implementation Notes

• The block configures pins as digital outputs through the MCHP_PORT mechanism
• Each valid pin is registered as {Task D<n> Running}{Task D<n>}15:1:<pin>
• Pin values of -1 are filtered out and do not affect any GPIO pin
• Pin assignments are stored in the block’s RTWdata.TaskPinProfile for code generation

Troubleshooting

Related Blocks

• MCU LOAD - CPU utilization monitoring
• MCU OVERLOAD - Overload detection