Application of SPMC65P2102A in soybean milk machine

1 Introduction
At present, people have higher and higher requirements for the quality of life. When people are busy with work, soymilk machine is a new type of household beverage machine. It uses soybean as raw material and directly processes mature hot soybean milk. If sesame, peanuts, almonds and other condiments are added to soybeans, delicious beverages of various flavors can be made. The soymilk machine consists of three parts: a mixer for crushing soybeans, a soymilk heater and a control circuit. The control circuit of the fully automatic soymilk machine developed by the single-chip microcomputer, as long as the start button is pressed, the soymilk machine starts working, and you can drink delicious and nutritious soymilk in a while. The whole process is fully automatically controlled by the single-chip microcomputer, making it more convenient and safer for you to use.
2 Functions of the soymilk machine
Separate heating: It has a separate heating function and can stop heating at any time.
Separate crushing: It has a separate crushing function, and the crushing is 15 seconds per time, and it will not stop in the middle.
Automatic work: The process is as follows: In the presence of water, the electric heating tube starts heating. When the water temperature rises to 82℃, the heating stops and the motor starts working 4 times. Then continue heating. When the foam produced by the soy milk hits the anti-overflow electrode, it switches to reduced power heating. Heating for 6 minutes ends and alarms.
The whole process is in a waterless alarm and stops working: During separate heating, separate crushing, and automatic operation, if the soy milk machine is lifted at any time, it will stop working and alarm. When the soy milk machine is put into the water again, it will return to the previous working state.
Reduced power heating: In automatic operation and separate heating mode, when the foam produced by the soy milk hits the anti-overflow electrode, it switches to reduced power heating.
Self-test mode: Press the "heating" and "crushing" keys at the same time for more than 2 seconds to enter the self-test mode. The buzzer and indicator light beep and flash 3 times at the same time, each time with an interval of 0.5 seconds, then the indicator light is always on, heating for 1 second, reducing the power to heat for 1 second, and the motor works for 1 second before all stop. The alarm mode is that the buzzer and indicator light beep and flash at the same time, each time with an interval of 1 second.
3 System overall plan introduction
The hardware block diagram is shown in Figure 3-1, with 3 sensors to measure water level, overflow, and temperature, 3 buttons, 1 buzzer output port, and 2 heating mode options.

Figure 3-1 Principle block diagram of the control system
4 System hardware design
The entire hardware system consists of two parts: the power board and the main control board. The power supply part, the button part, the sensor part, the motor and heating part, and the crystal oscillator clock part are shown in Figure 4-1.

Figure 4-1 Schematic diagram of the hardware of the soymilk machine
4.1 Power supply part
The power supply part mainly converts 220V into relay control power supply and system 5V power supply. The voltage in front of 7805 is used for relay control power supply. The 5V voltage generated after 7805 passes through a 0 ohm resistor and enters the control board to supply power to the entire system. See the schematic diagram in 4-2 [page]

Figure 4-2 Schematic diagram of the power supply part
4.2 Keyboard input circuit
The keyboard input circuit is shown in Figure 4-3. When a key is pressed, the corresponding IO port is pulled to a high level, and the CPU performs corresponding processing.

4.3 Sensor input circuit
The detection circuit is mainly composed of temperature sensor, water level probe and foam probe. The temperature sensor uses a thermistor with a negative temperature coefficient.

4.5 Control drive
circuit The working principle of the drive circuit is to output signals from the I/O port and control the relay through the Q2, Q3, and Q5 drive circuits. The control circuit is shown in Figure 4-5.

Figure 4-5 Control drive circuit

5 Introduction to chip features
SPMC65P2102A is an 8-bit industrial control microcontroller designed and developed by Lingyang Company. It adopts Lingyang SPMC65 core and supports bit operation instructions. It is suitable for some general small household appliances, such as soybean milk machines, coffee machines, range hoods, etc. [page]
The specific features of the chip are as follows:
Working voltage: 3.0V~5.5V
Working speed: 8MHz
Working temperature: -40℃~85℃
Super strong anti-interference, anti-static ESD protection capability
2K byte OTP ROM, 128 byte RAM
13 general input and output ports, all of which can be set to pull up, pull down and suspension mode
With Capture\\Compare\\PWM function
1 1Hz~62.5KHz time base
4-channel 10-bit precision ADC (with external reference voltage)
2 external interrupts, 5 internal interrupts
2 power saving modes: Halt, Stop
Buzzer output function
4.0V/2.5V optional low voltage reset function
Programmable watchdog function
Chip package diagram:

6 System Software Design

7 Conclusion
The progress of science and technology has made people's lives simpler and more enjoyable. The soymilk machine designed with SPMC65P2102A is safe and convenient. After busy work, people can drink a cup of nutritious soymilk and enjoy life from now on.
8 References
[1] Zhou Junxiong. Three-in-one fully automatic soymilk machine. Today's Technology, 2000.
[2] 28 domestic news. Household Appliance Technology, 2000.
[3] Chen Aijun, Huang Yongsheng. Everyone is satisfied with Keshun Electric Appliances. China Quality and Technical Supervision, 2000.
[4] Chen Aijun, Huang Yongsheng. Everyone is satisfied with Keshun Electric Appliances. China Technical Supervision, 2000.
[5] Liu Ling. Constant temperature controller using four comparators. Electronic Technology, 2000