Hello TI Team,
I am using the TMS320F280049C in my project and encountered an issue where CMPSS5 and CMPSS6 do not respond to input signals, while CMPSS3 works normally under the same conditions. I am reporting the issue here for further support.
1. Test Environment
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Device: TMS320F280049C
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Test code: TI official example project for CMPSS
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Test method: Added CMPSS3, CMPSS5, CMPSS6 for comparison under identical configuration
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Input: External analog voltage signal
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Reference: Internal DAC threshold
2. Configuration
All three CMPSS modules were configured with the same settings, including:
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High comparator enabled
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DAC reference enabled
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Same DAC threshold value
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Outputs routed to GPIO for observation
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Comparator hysteresis and filters disabled (same for all)
I also tested by setting DAC = 0, input 1.25 V, but CMPSS5/6 still show no output change.
3. Observation
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CMPSS3: Responds correctly to input voltage crossing the threshold.
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CMPSS5 & CMPSS6:
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No output toggling
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No change even when the threshold is set to 0
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No observable response at output pin or when reading internal status registers
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4. Additional Checks
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Verified the input voltage with oscilloscope
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Confirmed ADC channels connected to the same pins read correct voltages
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Swapped test boards:
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Some boards work fine
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A few boards consistently show CMPSS5/6 failure
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No conflicts with pin mux or other peripherals
5. Questions
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Are there known issues with CMPSS5 or CMPSS6 on certain lots of the F280049C?
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Could this be related to pin mux, analog routing, or silicon errata?
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Are there diagnostic registers I can check to further confirm CMPSS hardware failure?
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Do you recommend performing additional factory test patterns or self-test routines to validate the CMPSS hardware?
6. Attachment
I can provide:
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Test code snippet
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Register dump
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Video / screenshots of oscilloscope and output signals
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Affected device lot numbers
Thanks in advance. I appreciate your support.
Regards,
Tang
