[ESP8266]: Transparent mode

[paupoix]

Hi Community,

I'm working on a project with ESP-WROOM-02 module which embeds the ESP8266.
I'm using it to in gateway mode UART to TCP/IP (AT+CIPMODE=1 and AT+CIPSEND), the module is in station mode of course and up to date, the OTA update is always processed at startup.

This is the environment :
- LPC MCU sends data to ESP through the UART (baudrate : 2 880 000 = 115200 * 25). The data destination is a TCP/IP server (Websocket on top of)
- Data packet size is from 1800 bytes and send every 20-25 ms (100 kB/s). I know, mimimum 20 ms between two packets is specified in ESP8266 AT command user manual and we followed this recommendation of course.

This is my problem :
When we send a certain amount of data, not constant, some data (around 180 bytes) are lost and the WebSocket server is gone away due to understanding data.
We spied the UART link to be able to confirm the whole data are sent to ESP module without lost. We made a comparison between this UART spy and a Wireshark capture to find this lost.

We tried to :
- decrease packet size but the problem steel there, except if the data size are less than 128B.
- decrease the packet sending frequency, the problem disappeared if there is 300 ms between 2 packet.
- decrease the UART baudrate but there is no impact.

Do you know how we can fix this problem ? Is it already known ? I don't think we use the ESP module in these limits ?

Thanks in advance for your help

[Her Mary]

Maybe you can try to enable the UART flow control.