Frequently Asked Questions

Note: Product documentation is provided after purchase.

What is the relationship between DOIT and Espressif?

Espressif supplies the chips used in the ESP-series modules. DOIT develops and manufactures the ESP-series modules. Espressif Information Technology is a shareholder of DOIT. Please refer to Tianyancha for further details.

What is the difference between the ESP8285 and ESP8266?

The ESP8285 integrates 1 MB of flash memory into the ESP8266 chip. Its package and low-level protocols are fully compatible with the ESP8266. The ESP8285 offers higher integration and better high-temperature performance. Typical external flash memory on the market is rated for temperatures up to 85°C.

Which module should ESP8266 customers choose?

For surface-mount applications, we recommend the ESP-F/F1 or ESP-M1/M2. For through-hole applications, we recommend the ESP-01S.

What is the difference between the ESP-F, ESP-12E, and ESP-12F?

The ESP-F uses a four-layer PCB, while the ESP-12E and ESP-12F use two-layer PCBs. If certification and product quality are priorities, choose the ESP-F, which supports FCC, CE, and SRRC certification. Its four-layer PCB includes a ground-plane layer for a more stable signal and Wi-Fi certification compliance.

What are the performance specifications of ESP-series modules?

ESP-series modules run at 80–160 MHz. The maximum UART transfer rate is 115200 × 40 (approximately 4.5 Mbps). ESP8266 modules support up to 16 MB of external storage. The ESP series provides 160 KB of RAM, with less than 50 KB available to user applications. The internal ADC has 12-bit effective resolution, while the API returns a 10-bit value.

Which ESP-series module offers the longest transmission distance?

Transmission distance depends on the antenna. In open-field testing, ESP-F/M/S modules reach approximately 150 m, ESP-12F/12E modules approximately 100 m, and ESP-01/01S/07 modules approximately 70 m.

Can ESP-07 modules share an antenna?

They can share an antenna, but this is not recommended because antenna efficiency will be significantly reduced.

What is the maximum packet length for TCP and UDP transmission?

The maximum TCP packet length is 1460 bytes, and the maximum UDP packet length is 1472 bytes.

Why can packet loss occur during transparent transmission?

Packet loss may occur when serial flow control is not enabled.

Product Documentation

Usage instructions are available at wiki.doit.am.

1. Overview

The ESP-01S Wi-Fi module is a low-power, cost-effective embedded wireless network control module. It is suitable for IoT applications such as smart grids, building automation, security systems, smart homes, and remote healthcare.

The module’s ESP8266 core processor integrates the industry-leading Tensilica L106 ultra-low-power 32-bit microcontroller in a compact package. It includes a 16-bit reduced instruction mode, supports 80 MHz and 160 MHz clock frequencies and RTOS, and integrates Wi-Fi MAC/BB/RF/PA/LNA with an onboard antenna.

The module supports IEEE 802.11 b/g/n and a complete TCP/IP protocol stack. It can add network connectivity to existing devices or operate as a standalone network controller.

2. Hardware Specifications

• Operating voltage: 3.3 V (3.0–3.6 V)
• Operating temperature: −40°C to 85°C
• CPU: Tensilica L106
• Available RAM: 50 KB
• Flash: 32 Mbit
• Wireless standard: IEEE 802.11 b/g/n
• Frequency range: 2.4–2.5 GHz (2400–2483.5 MHz)
• Processor: Integrated Tensilica L106 ultra-low-power 32-bit MCU with 16-bit reduced instruction mode, supporting 80 MHz and 160 MHz operation and RTOS
• Security: WPA/WPA2
• Interfaces: UART, I²C, GPIO, PWM, SDIO, SPI, ADC, and IR
• ADC: Integrated high-precision 10-bit ADC
• Protocols: TCP, UDP, HTTP, and FTP
• RF integration: TR switch, balun, LNA, power amplifier, and matching network
• Power integration: PLL, voltage regulator, and power-management components
• RF output: +20 dBm in 802.11b mode
• Average operating current: 80 mA
• Deep-sleep current: 20 µA
• Shutdown current: Less than 5 µA
• Application-processor interfaces: SDIO 2.0, SPI, and UART
• Wake-up time: Connects and transmits data packets within 2 ms
• Standby power: Less than 1.0 mW (DTIM3)
• Firmware support: Local serial flashing, cloud OTA upgrades, and host download flashing
• Wireless modes: Station, SoftAP, and SoftAP + Station
• Module dimensions: 24 × 16 × 3 mm

4. Pin Diagram

Connection Notes

1. Supply the module with 3.3 V DC and at least 500 mA.
2. The maximum output current for a Wi-Fi module I/O pin is 12 mA.
3. The NRST pin is active low; the EN pin is active high.
4. To enter firmware-upgrade mode, hold GPIO0 low and then reset or power-cycle the module. For normal operating mode, hold GPIO0 high and then reset or power-cycle the module.
5. Connect the Wi-Fi module’s RXD to the external MCU’s TXD, and connect the Wi-Fi module’s TXD to the external MCU’s RXD.

5. Product Photos