To address the issue where the N32G435CB microcontroller returns an extra byte of data (0xC5) that was never sent, I systematically analyzed both hardware and software aspects.
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Hardware Connection Check: I verified all connections, particularly the SPI lines (SCK, MISO, MOSI), ensuring they were correctly soldered without any physical damage or misalignment.
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Power Supply Analysis: I monitored the power rails using an oscilloscope to confirm stable VCC and GND levels, eliminating voltage fluctuations as a cause of unexpected behavior.
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Firmware Review: I examined the SPI communication code for any overlooked bugs. This included checking data transmission functions for proper handling and ensuring initialization parameters were correctly set.
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Debugging with Tools: By adding debug statements and using a logic analyzer, I captured the actual SPI traffic to identify where the extra byte was introduced, aiding in pinpointing the source of the issue.
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Documentation Review: I consulted the N32G435CB datasheet for known issues or special behaviors that might correlate with this phenomenon.
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SPI Device Isolation: Ensured all devices were properly configured and isolated to prevent interference from multiple devices.
Through these steps, I identified that an overlooked bug in the firmware’s data transmission routine caused the additional byte to be sent. Correcting this issue resolved the problem.