Troubleshooting

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This page provides solutions to common issues encountered when using the MPLAB Device Blocks for Simulink. Issues are organized by category for quick reference.

Compilation Errors

Problem: Compiler Not Found

Symptom: Build fails with error message: "Compiler not found" or "xc16-gcc is not recognized"

Solutions:

1. Verify compiler installation:

   • Run picInfo('check') to check detected compilers
   • Ensure compiler is installed in default location:
     • XC16: C:\Program Files\Microchip\xc16\
     • XC-DSC: C:\Program Files\Microchip\xc-dsc\
     • XC32: C:\Program Files\Microchip\xc32\

2. Refresh MATLAB compiler cache:

   >> RTW.TargetRegistry.getInstance('reset')
   >> rehash toolboxcache
   

3. Manual configuration: See Compiler Setup → Manual Configuration

4. Reinstall compiler: Download from microchip.com/compilers

Problem: Wrong DFP (Device Family Pack)

Symptom: Build fails with: "Device not supported" or "Cannot find device header file"

Solutions:

1. Install correct DFP:

   • Open MPLAB X IDE
   • Tools → Packs → Device Family Pack Management
   • Select your device family, click “Install Latest”

2. Update DFP to latest version: Older DFPs may not support newer devices

3. Verify device name: Check Master block device selection matches exactly (case-sensitive)

Problem: Linker Errors - Undefined Reference

Symptom: Build fails with: "undefined reference to 'functionName'" or "undefined symbol"

Common Causes:

• Missing compiler library
• Wrong compiler version (too old)
• Missing DFP peripheral library

Solutions:

1. Check compiler version: Ensure minimum version requirements are met (Compiler Setup )
2. Update DFP: Install latest Device Family Pack
3. Check function name spelling: Verify block parameter values are correct
4. Enable required libraries: Some blocks require additional compiler libraries

Problem: Linker Errors - Memory Overflow

Symptom: Build fails with: "section overflow", "program memory exceeds available space", or "data memory exceeds available space"

Solutions:

1. Enable optimization:

   • Add Compiler Options Block
   • Set optimization to -O2 (free) or -O3 (PRO license)

2. Reduce model size:

   • Remove unused blocks
   • Simplify algorithms
   • Use external code/libraries for large functions

3. Select larger device: Consider microcontroller with more Flash/RAM

4. Check memory allocation:

   • Review linker script memory regions
   • Verify stack and heap sizes are appropriate

External Mode Issues

Problem: Cannot Connect to Target

Symptom: Simulink shows: "Cannot connect to target" or connection timeout after clicking “Connect to Target”

Solutions:

1. Check physical connection:

   • Verify USB/UART cable is connected
   • Try different USB port
   • Check cable quality (replace if needed)

2. Verify COM port:

   • Open Device Manager (Windows)
   • Check which COM port is assigned
   • Update External Mode settings to match

3. Verify UART configuration:

   • Ensure UART block baud rate matches External Mode setting
   • Check UART TX/RX pins are connected correctly
   • Verify UART peripheral is not used by other code

4. Check target is running:

   • Add LED toggle in initialization code
   • Verify code is executing after programming

5. Restart devices:

   • Unplug/replug USB cable
   • Press reset button on target board
   • Close and reopen Simulink model

Problem: Connection Drops Randomly

Symptom: Connection works initially but drops during operation or parameter tuning

Solutions:

1. Reduce logged signals: Too many signals saturate communication bandwidth

2. Increase baud rate:

   • Try 230400 or 460800 instead of 115200
   • Ensure UART block matches External Mode setting

3. Check electrical noise:

   • Use shielded cable
   • Keep cable away from motor power lines
   • Add ferrite bead to cable

4. Disable USB power management:

   • Device Manager → USB Controllers → Properties
   • Power Management tab
   • Uncheck “Allow computer to turn off this device”

Problem: Baud Rate Mismatch

Symptom: Garbled data, connection timeouts, random characters in Simulink

Solution:

Ensure these three settings match exactly:

1. External Mode baud rate (Model Configuration Parameters → Code Generation → Interface)
2. UART block baud rate parameter
3. Physical UART hardware register (auto-configured, but verify)

Common baud rates: 115200, 230400, 460800

Hardware Connection Issues

Problem: Programmer Not Detected

Symptom: Build succeeds but programming fails: "No tool connected" or "Programmer not found"

Solutions:

1. Check USB connection: Ensure programmer (ICD, PICkit, etc.) is plugged in

2. Verify programmer is powered: Some programmers have power LED

3. Install MPLAB X IDE: Required for programmer drivers

4. Update programmer firmware:

   • Open MPLAB X IDE
   • Tools → Options → Embedded
   • Check “Update firmware automatically”
   • Connect programmer and allow firmware update

5. Run picInfo check:

   >> picInfo('check')
   

   Should list detected programmers

Problem: Device ID Mismatch

Symptom: Programming fails with: "Device ID mismatch", "Target device not detected", or "Device ID: 0x00000000"

Solutions:

1. Check target power: Ensure microcontroller is powered (3.3V or 5V depending on device)

2. Check programmer connections: Verify ICSP pins (PGC, PGD, MCLR, VDD, GND) are connected

3. Verify device selection: Ensure Master block device name matches physical chip

4. Check for damaged chip: Try programming with MPLAB X IDE to verify hardware

5. Check ICSP voltage: Some programmers provide power, some require external power

Model Configuration Issues

Problem: Missing Master Block

Symptom: Build fails immediately: "Model must contain MCHP_Master block"

Solution:

Add the MCHP Master Block to your model:

1. Open MCHP Blockset library
2. Drag MCHP_Master block to model
3. Double-click to configure target device
4. Rebuild model

Problem: Sample Time Conflicts

Symptom: Simulation or build fails with: "Sample time conflict" or "Inconsistent sample times"

Solutions:

1. Check all block sample times: Ensure blocks have compatible sample times

   • Right-click block → Block Parameters → Sample time
   • Use inherited (-1) where possible

2. Review model hierarchy: Subsystem sample times must be compatible with parent

3. Use multi-rate scheduler: If model has multiple sample times, enable multi-tasking (Scheduler Guide )

Problem: Code Generation Fails

Symptom: Simulink code generation step fails before compiler is invoked

Solutions:

1. Check block parameters: Some blocks have parameter constraints (e.g., PWM frequency limits)

2. Verify license: Ensure Embedded Coder license is active:

   >> license('test', 'RTW_Embedded_Coder')
   

3. Clear cache and rebuild:

   >> bd close all
   >> clear all
   >> rehash toolboxcache
   

   Then reopen model and rebuild

4. Check MATLAB version compatibility: See Installation Requirements

Performance Issues

Problem: Model Runs Slow on Hardware

Symptom: Control loop frequency is lower than expected, or CPU utilization is near 100%

Solutions:

1. Enable optimization:

   • Add Compiler Options Block
   • Set optimization level to -O2 or -O3

2. Profile execution time: Use PIL Testing to identify slow functions

3. Optimize algorithm:

   • Reduce sample rate for non-critical tasks
   • Simplify calculations
   • Use lookup tables instead of real-time calculations

4. Switch to multi-tasking scheduler: See Scheduler Guide

5. Check MCU load: Add MCU Load Block to monitor CPU utilization

Problem: Real-Time Deadline Missed

Symptom: "MCU Overload" indicator triggers, or timing violations in PIL test

Solutions:

1. Increase sample period: Reduce execution frequency if possible

2. Enable multi-tasking: Allows preemption of slow tasks by fast tasks

3. Optimize code: Follow Performance Issues solutions above

4. Upgrade microcontroller: Consider faster device (e.g., dsPIC33C → dsPIC33A)

MATLAB/Simulink Issues

Problem: Blocks Not Visible in Library

Symptom: MCHP Blockset library appears empty or blocks are missing

Solutions:

1. Refresh toolbox cache:

   >> rehash toolboxcache
   >> sl_refresh_customizations
   

2. Verify installation:

   >> picInfo
   

3. Reinstall blockset: Uninstall and reinstall from MATLAB Add-On Manager

Problem: Documentation Not Found

Symptom: Clicking “Help” on a block shows “Page not found”

Solution:

Rebuild documentation search index:

>> builddocsearchdb(fullfile(fileparts(which('MCHP_dsPIC_stf.tlc')), '../', 'doc'))

Then restart MATLAB.

Getting Additional Help

If your issue is not listed here or solutions don’t resolve the problem:

1. Check Model Configuration

Run comprehensive diagnostics:

>> picInfo('check')

2. Review Documentation

• Installation Guide
• Compiler Setup
• External Mode Guide

3. Search Support Forums

Microchip MATLAB Forum:

🔗 forum.microchip.com - MATLAB Section

MathWorks File Exchange Discussion:

🔗 MPLAB Device Blocks Discussion Panel

4. Report an Issue

When reporting issues, include:

• MATLAB version
• Blockset version (picInfo)
• Compiler version (picInfo('check'))
• Target device family and part number
• Error message (full text)
• Steps to reproduce
• Screenshots if applicable

Diagnostic Commands Summary

See Also

• Installation Guide
• Compiler Setup
• External Mode
• PIL Testing
• Scheduler & Multitasking