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Renesas Electronics America - Knowledgebase

How can a H8S/21xx support 24 ADC channels if it only has 8 inputs?

Latest Updated:03/18/2009


How does the H8S/21xx support 24 ADC channels when the ADC peripheral only has 8 inputs ?


The H8S/21xx series has a dedicated analogue input port Port 7. These 8 inputs are fed directly into the ADC multiplexer. In addition to Port 7 the inputs signals of Port A and Port 6 can be directed to the ADC. Input signals on Port A are multiplexed into channel AN6 and input signals on Port 6 are multiplexed into channel AN7. It is therefore possible to have 24 analogue input signals multiplxed into the 8 channel ADC. It should be noted that there is a small reduction in accuracy when using the Port A and Port 6

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