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Preface

STM32---------ADC (Analog/Digital Converter)

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Tip: The following is the main content of this article, and the following cases are for reference

1. ADC definition

ADC, abbreviation of Analog-to-Digital Converter, refers to an analog//digital converter or analog-to-digital converter. It refers to a device that converts continuously changing analog signals into discrete digital signals. Real-world analog signals, such as temperature, pressure, sound or images, need to be converted into digital forms that are easier to store, process and emit. An analog/digital converter can implement this function and it can be found in a variety of different products.

2. Analog signal

analog signal
Temperature: Temperature sensor, DHT11
Humidity: Humidity sensor, DHT11
Sound: Audio chip for recording, WM8906
Image: Sony IMX386/IMX283 sensor
Sensor converts analog signals into digital signals

An analog signal means that the numerical value is continuous, that is, the number of numerical values is infinitely large.

3. Digital signal

Digital Signal:
HD digital TV, MP3, JPG files
Features: represented by binary, the values are discrete and discontinuous

Digital signals means that the values are discontinuous, and the number of values is limited.

IV. The process of analog-to-digital conversion

V. Characteristics

12-bit accuracy: 3300mv/4096=0.8mv, that is, the ADC can only distinguish it as long as the voltage value changes by ±0.8mv.
10-bit accuracy: 3300mv/1024=3.22mv, that is, the ADC can only distinguish it as long as the voltage value changes by ±3.22mv.
8-bit accuracy: 3300mv/256=12mv, which means that the ADC can only distinguish it as long as the voltage value changes by ±12mv.
6-bit accuracy: 3300mv/64=51.5625mv, that is, the ADC can only distinguish it as long as the voltage value changes by ±51.5625mv.

6. Hardware circuit

1. Schematic diagram

The VREF pin is the reference voltage, which can be understood as determining the maximum value measured by the ADC.

The connection of the VREF pin determines the current voltage measurement range of 0V~3.3V. Generally speaking, this pin cannot exceed the power supply voltage of the chip!

2. Pins used for adjustable resistors

3. The ADCs supported by different pins are different.

1.
The PC0 pin can use ADC1, ADC2 or ADC3 converters, using the 10th input channel!
2.

The PF10 pin can only use the ADC3 converter, using the 8th input channel!

4. Storage alignment method

7. Thinking questions

Why do the result values obtained through ADC hardware still have to be converted into voltage values? What is the basis?

8. Source code download

Download ADC source code

Summarize

The above is what we are going to talk about today. This article only briefly introduces the use of ADC, and some other usage modules of STM32. Please follow the blogger’s other articles or follow the blogger to wait for subsequent releases.