I describe the problem that happens with the CY8C5267AXI-LP051 processor.
I use the free-running 12-bit ADC SAR to capture 2 analog signals with an analog 2-input multiplexer. The acquisition system is organized with a timer that generates an interrupt every 50 micro seconds. At each interrupt the ADC_SAR is started and at the end of the conversion the result is memorized and finally the next channel is selected for acquisition at the new interrupt. The system works correctly for at least a couple of weeks, then progressively, the ADC_SAR fails. It happens that, regardless of which input the ADC converts, the result becomes a constant number (eg 799), even if the value of the analog signal is zero. This problem is systematic, on 5 devices tested for prolonged working time all after at least 2 weeks of intense work have the same problem. Can you give me an explanation and a possible solution? I enclose the images of the configuration of the ADC_SAR and a typical image of the analog signals that are normally acquired.