#### ESP-01S Basic Features
* Complete 802.11b/g/n Wi-Fi SoC module
* Built-in Tensilica L106 ultra-low power 32-bit micro MCU, main frequency supports 80 MHz and 160 MHz,
supports RTOS
* Built-in 1-channel 10-bit high-precision ADC
* Supports UART/GPIO/PWM interface
* Adopts DIP-8 package
* Integrated Wi-Fi MAC/BB/RF/PA/LNA
* Supports multiple sleep modes, standby power consumption as low as 1.0mW
* Serial port rate can reach up to 4Mbps
* Embedded Lwip protocol stack
* Support STA/AP/STA+AP working mode
* Support Android, IOS Smart Config (APP)/AirKiss (WeChat) one-click network configuration
* Support serial port local upgrade and remote firmware upgrade (FOTA)
* General AT commands can be quickly used
* Support secondary development, integrated with Windows and Linux development environment
#### CH340
1. CH340C/N/K/E and CH340B have built-in clocks, no external crystal is required
2. CH340K has three built-in diodes to reduce the current backflow between the MCU's I/O pins when the power supply is independent. The bottom board of CH340K is 0# pin GND, which is an optional connection; 3# pin GND is a necessary connection.
3. **V3 pin: connect VCC input external power supply at 3.3V power supply voltage, and connect an external 0.1uF decoupling capacitor at 5V power supply voltage**
4. DTR#: output, MODEM contact output signal, data terminal ready, low (high) valid
5. RTS#: output, MODEM contact output signal, request to send, low (high) valid
6. CTS#: input, MODEM contact input signal, clear to send, low (high) valid
7. **CH340 chip has built-in USB pull-up resistors, UD+ and UD- pins should be directly connected to the USB bus**.
8. MCU serial port one-key download solution without peripheral circuit (Qinheng official): https://www.wch.cn/application/575.html
![Package picture.png]

#### Automatic download circuit
NMOS model: https://item.szlcsc.com/63955.html The reason for using this is to clear the inventory, and it can be replaced with other models and can be used as well.
![Snipaste_2023-04-06_20-27-49.png]

#### Test program
```c
#define led 2
void setup() {
pinMode(led, OUTPUT);
}
void loop() {
digitalWrite(led, HIGH);
delay(1000);
digitalWrite(led, LOW);
delay(1000);
}
```
#### Actual picture
![2.png]

![1.png]