NEXUSX: USE_DSHOT_DMAR, use TIM2 instead of TIM5

[functionpointer]

User description

Activate USE_DSHOT_DMAR for target NEXUSX.

Also move pins labelled "RPM" and "TLM" (PA2 and PA3) to timer2 instead of timer5.
This lifts the previous limitation of 7 motor outputs. Apparently, DSHOT_DMAR can only handle 4 timers for motors.

The move causes the pin labelled "TAIL" to be on the same timer as "RPM" and "TLM", removing a small amount of flexibility.
However, it is still possible to have 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 motors without wasting a pin to timer limitations if the user selects clever timer assignments in the mixer tab.

Furthermore, this PR sets TIM1 as MOTOR by default, which is mapped to the "ESC" pin.
This creates sane defaults for platforms with 1 and 4 motors without user intervention.

This PR is the result of investigation of changes proposed in #11120

I have tested:

• MULTISHOT with 7, 8 and 9 motor outputs using oscilloscope
• DSHOT600 with 7, 8 and 9 motor outputs using oscilloscope
• Servo outputs on remaining pins
• Default mixer assignments for quadcopter and plane with tail

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PR Type

Enhancement

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Description

• Enable DSHOT_DMAR support for NEXUSX target

• Reassign RPM and TLM pins from TIM5 to TIM2

• Increases motor output limit from 7 to 9

• Set TIM1 as default motor output for sane defaults

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Diagram Walkthrough

flowchart LR
  A["DSHOT_DMAR enabled"] --> B["Max 4 timers supported"]
  B --> C["Reassign TIM5 to TIM2"]
  C --> D["Motor limit: 7 → 9"]
  E["TIM1 default motor"] --> F["Sane defaults for 1/4 motors"]

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File Walkthrough

	Relevant files
Enhancement	target.h Enable DSHOT_DMAR feature flag                                                      src/main/target/NEXUSX/target.h Added USE_DSHOT_DMAR define to enable DSHOT DMA support Activates hardware DMA capability for improved DSHOT performance +2/-0
Configuration changes	target.c Reassign RPM and TLM pins to TIM2                                                src/main/target/NEXUSX/target.c Migrated RPM pin (PA2) from TIM5 CH3 to TIM2 CH3 Migrated TLM pin (PA3) from TIM5 CH4 to TIM2 CH4 Consolidates timer usage to support DSHOT_DMAR limitation of 4 timers max +2/-2      config.c Configure TIM1 as default motor output                                      src/main/target/NEXUSX/config.c Set TIM1 (ESC pin) as default motor output mode Provides sensible defaults for single and quadcopter configurations Eliminates need for manual timer assignment in common use cases +3/-0

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[qodo-merge-pro]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
🟢	No security concerns identified No security vulnerabilities detected by AI analysis. Human verification advised for critical code.
Ticket Compliance
⚪	🎫 No ticket provided Create ticket/issue
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: No auditing: The new configuration that sets a default motor output adds no logging or audit trail for this critical configuration change, but target config files may not handle runtime auditing. Referred Code // default "ESC" pin to be a motor timerOverridesMutable(timer2id(TIM1))->outputMode = OUTPUT_MODE_MOTORS; } Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: No null checks: Calls to configuration mutators (e.g., timerOverridesMutable(timer2id(TIM1))) add no error handling or validation, but these APIs may be guaranteed non-null in this environment. Referred Code timerOverridesMutable(timer2id(TIM1))->outputMode = OUTPUT_MODE_MOTORS; } Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Hardware conflicts: New timer assignments (TIM2 CH3/CH4 on PA2/PA3) note UART2 conflicts without validating or enforcing safe configuration at runtime. Referred Code DEF_TIM(TIM2, CH3, PA2, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "RPM", clashes with UART2 TX DEF_TIM(TIM2, CH4, PA3, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "TLM", clashes with UART2 RX Learn more about managing compliance generic rules or creating your own custom rules

Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Fix timer resource conflict Move the RPM and TLM pin definitions from TIM2 to TIM1 to resolve a timer resource conflict, as a single timer cannot be used for both motor output and sensor input simultaneously. src/main/target/NEXUSX/target.c [32-37] DEF_TIM(TIM2, CH1, PA15, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "TAIL" DEF_TIM(TIM1, CH2, PA9, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "ESC" +DEF_TIM(TIM1, CH3, PA2, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "RPM", clashes with UART2 TX +DEF_TIM(TIM1, CH4, PA3, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "TLM", clashes with UART2 RX -DEF_TIM(TIM2, CH3, PA2, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "RPM", clashes with UART2 TX -DEF_TIM(TIM2, CH4, PA3, TIM_USE_OUTPUT_AUTO, 0, 0), // labelled "TLM", clashes with UART2 RX - [To ensure code accuracy, apply this suggestion manually] Suggestion importance[1-10]: 9 __ Why: The suggestion correctly identifies a critical hardware resource conflict where TIM2 is used for both motor output and timer inputs, which would cause either motors or sensors to fail.	High
Learned best practice	Validate timer override existence Check that the timer override entry exists before writing to it to avoid null or invalid access when TIM1 isn't mapped. src/main/target/NEXUSX/config.c [40-41] // default "ESC" pin to be a motor -timerOverridesMutable(timer2id(TIM1))->outputMode = OUTPUT_MODE_MOTORS; +timerOverride_t *ovr = timerOverridesMutable(timer2id(TIM1)); +if (ovr) { + ovr->outputMode = OUTPUT_MODE_MOTORS; +} Apply / Chat Suggestion importance[1-10]: 5 __ Why: Relevant best practice - Guard against invalid states by validating timer availability before overriding configuration.	Low
More

[sensei-hacker]

Before I merge this, can you please comment just very briefly on whether you think the suggestions from the bot are useful?
The bot is very often wrong, but sometimes it has good suggestions.

[functionpointer]

Suggestion 1 is physically impossible, TIM1 cannot be used on the RPM and TLM pins. See the second table in the readme https://github.com/iNavFlight/inav/blob/master/src/main/target/NEXUSX/README.md

Suggestion 2 makes no sense as TIM1 will always be mapped. It is defined that way in target.c. Furthermore, this exact way of predefined timer assignments is used by plenty of other targets already.

[sensei-hacker]

Suggestion 1 is physically impossible

Sometimes the bot reminds me of my boss. 😁