FAQ:
How many UART port does ESP8266 have?
ESP8266 has two UART ports, UART0 and UART1. UART0 has Tx and Rx pins for data transmission, while UART1 only has Tx for printing debug log. Its Rx pin is occupied by SPI-flash.
OTA failed, what could be the reasons?
There could be many common reasons for OTA failure. We recommend referring to the document ESP8266 FOTA Guide before you use the FOTA APIs.
Here are some quick checklist to troubleshoot OTA failure:
• Make sure that you select the correct flash size when downloading the firmware to flash.
• The first time you download a new firmware, always also download blank.bin.
• Confirm that user1.bin and user2.bin (optional) downloaded to the correct locations.
• Make sure you generate user1.bin and user2.bin with the same flash/boot configuration options.
Why does SmartConfig fail?
Here are some probable reasons why SmartConfig might fail:
• APP version is not matched with SDK or SmartConfig version.
• The router under configuration is a 5 GHz-only router.
• Some other API was called during SmartConfig (please do not call any APIs under SmartConfig is done).
• When using AT command, do not call smartconfig_stop before device gets IP from router.
If the above do not solve your problem, please send us the debug log so that we can analyze the problem.
Why do I have problem connecting to router with IP 192.168.4.X in SoftAP + Station mode?
Default IP address of ESP8266 SoftAP is 192.168.4.1.
The ESP8266 cannot distinguish if the IP address of the SoftAP and the Station are both in the same subnet, in this case, 192.168.4.x. Sorry for the inconvenience.
How to download firmware to flash in the development phaseand the mass production phase?
In the development phase:
The flash memory can be programmed by connecting the ESP8266 to the computer using a UART link. This can be achieved with a USB-UART converter for PCs that no longer have serial ports available externally. For instructions on how to use the Espressif official flash download tool, please refer to the document ESP8266 SDK Getting Started Guide.
• Download tool: espressif.com/en/support/download/other-tools
• Download method: espressif.com/en/support/download/documents
