#The 8th Lichuang Electronic Competition# Digital tube clock

 1. Introduction to project functions
Digital tube desktop time, display time, set alarm clock and display temperature and humidity.
 
2. Project attributes The
project is a standard project of the 2023 EDA Summer Training Camp of LiChuang. It adopts a public schematic diagram and makes some adjustments to the components on the settlement body. 
3. The open source agreement
is completely open source.
 
 
4. Hardware part
1) TYPE-C power supply and indication

add CC identification resistor, which is commonly used for some fast charging 5V input identification, and the green LED is an external power indicator.
 
2) Lithium battery power supply part
When the external typec power supply is used, the P-MOS tube G level is high level cut-off and turned on, and the lithium battery is not powered;
when VBUS has no input, the P-MOS has a negative potential due to the body diode G level, the MOS tube is turned on, and the lithium battery is connected to the back-stage circuit for power supply.
 
3) When the lithium battery charging circuit
is powered by an external USB, the circuit TP4056 charges the lithium battery. The circuit is drawn according to the standard circuit in the data sheet, without temperature control.
The chip PROG guide is the charging current production pin. The data relationship is as follows and can be modified as required.
4) DHT11 temperature and humidity detection
is pulled up by a 10K resistor, and data transmission is carried out through the P301 port of the microcontroller.
 
5) Touch button sensing circuit
The Renesas microcontroller has a built-in touch function. The touch button function can be actually touched through a simple peripheral circuit. The touch sensor is connected to the P015 pin of the microcontroller.
6) The buzzer alarm circuit
is driven by the P302 pin of the microcontroller according to the setting output PWM to drive the buzzer.
 
7) Main control chip circuit
The main control adopts the Renesas R7EA2F1A72DFL basic low-power microcontroller, and the basic parameters are:
CPU core: ARM-M series CPU maximum main frequency: 48MHz Operating voltage range: 1.6V~5.5V Program storage capacity: 64KB GPIO port number: 40 ADC: 12 bits.
 
8) Main control basic peripheral circuit
 
5. The software part
uses E2studio, which is written and modified according to the tutorial. The function keys added and reduced are adjusted, and the fourth key is used to display temperature and humidity.