System and method for testing analog to digital converter embedded in microcontroller

摘要

A tester system tests the transfer characteristics and operability of an analog to digital converter (ADC) embedded in a microprocessor. The tester generates a sequence of analog signal test values, and prompts the microprocessor to read and convert each test value. The microprocessor sets up a table in its internal memory, the table having one tally value for every possible code output by the embedded ADC. After the embedded ADC converts each test value, the microprocessor reads the digital value output by the embedded ADC and increments a corresponding tally value in its internally stored table. When the sequence of tests is completed, the microprocessor transmits the entire table of tally values to the tester. The tester then performs a well known set of calculations on the tally data to determine the transfer characteristics and operability of the embedded ADC. By performing all tally operations in the microprocessor under test, the test sequence can be performed much more quickly than if each converted value were separately transmitted by the microprocessor to the tester. In addition, the tallying operation of the microprocessor simulates normal operation of the microprocessor while performing analog to digital conversions, and thus the embedded ADC is subjected to electromagnetic noise characteristic of the microprocessor under normal operation.