Update 03_ESP-M1.rst

source/WiFi Module/03_ESP-M1.rst

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 ESP-M1/M2
 ==============================
 
+The sell information can be visited at our link: M1:  `www.vvdoit.com <http://vvdoit.com/official-doit-10pcspack-mini-ultra-small-size-esp-m1-from-esp8285-wifi-module-serial-wireless-iot-compatible-esp8266-8266-diy-p779628.html>`_, and M2 `www.vvdoit.com <http://vvdoit.com/official-doit-5pcspack-mini-ultra-small-size-esp-m2-esp8285-wifi-module-serial-wireless-diy-iot-compatible-with-esp8266-8266-p779710.html>`_
+
 Introduction
 ------
 The WiFi module ESP-M is manufactured by using a high-performance chip ESP8285. This small chip is encapsulated an enhanced Tensilica’sL106  diamond series 32-bit kennel CPU with a SRAM. Thus, ESP8285 has the complete function Wi-Fi function; it not only can be applied independently, but can be used as a slaver working with other host CPU. When ESP8285 is applied as a slaver, it can start from the onboard Flash.  The built-in high-speed buffer is not only benefit to improve the system performance, but optimize the store system. In addition, ESP8285 can be used as Wi-Fi adapter by SPI/SDIO or I2C/UART interface, when it is applied to other MCU design.