1. Introduction

Previously, we tested the input voltage characteristics of the ports in the STC32C030 microcontroller. A signal source DG1062 was used to generate a peak 10V sine AC signal. It can be observed that the voltage at the microcontroller’s IO port is limited to around 9V. So what are the specific characteristics of the input voltage and current? Below, we will test the IO ports in the F030 microcontroller and calculate the corresponding current characteristics using resistor R1.

2. Measurement Results

On the produced circuit board, the test port was set as the input port. A voltage signal with a peak of 10V was generated using DG1062. The voltage signal measured after 100 ohms shows a variation. It can be seen that when the input voltage exceeds 4V, the voltage change becomes slower. The highest voltage exceeds 6V.

Next, we measure the input current by measuring the current on the 100 ohm resistor in series with the input port. The DG1766 provides an input voltage from 0V to 10V, allowing us to read the input port voltage and subsequently plot the relationship between input voltage and input current. The measurement results indicate that when the input voltage exceeds 3.7V, the input current begins to rise sharply. Particularly at 5V, the input current reaches 5mA.

The input port mode was set to analog input mode. From the measurement results, it can be seen that the relationship between input voltage and current remains unchanged.

※ Conclusion ※

This article tested the volt-ampere characteristics of the IO ports of the F030 microcontroller. From the measurement results, it can be concluded that when the input voltage exceeds 3.7V, an external current begins to flow in. At 5V, the incoming current is approximately 5mA. Therefore, care should be taken to avoid this situation during application.