nice answer from ESP_Angus - but why there is no https_mbedtls server example? If mbedtls is the library to prefer I would expect that there are more and better examples...

thank you for your fast answer.
yes, I will be using FAT filesystem with the in esp-idf provided C library. The webpages of course will only be read; so, a simultaneous read of the same file from two different tasks needs to be possible. I guess your answer gives green light for this approach, right?

I am trying to implement a webserver which serves the webpages stored on an SD card. It also should be able to serve more than one simultaneous connection. For this the esp-idf driver for the SD card needs to be reentrant. Is this the case?

Now I saw that there is a bt_spp_acceptor and bt_spp_initiator example available. This seems to be the "missing" BT-classic SPP profile. Has anybody tested it?

My current SW compiles o.k. but during startup of the µC I receive strange messages (in yellow): 0x40080000: _WindowOverflow4 at E:/msys32/opt/esp/esp-idf/components/freertos/xtensa_vectors.S:1685 and 0x400d0018: _flash_cache_start at ??:? and 0x4008bfa4: bb_init at ??:? Do I need to worry about the...

now I fixed my problem: it was related to a race condition between incoming and outgoing telegrams. Now btStack works. Unfortunately even after tuning everything the the BT communication is much slower than the direct serial communication (approx. factor 2).
@loboris: Thanks for your support.

now I also changed hci_dump.c and now there is no logging any more. But my problem remains the same: the communication is too slow. Can you check how fast you can exchange data?

using esp_log_level_set("[BT_STACK]", 3); you can only switch off logging of the esp-idf functions. The btstack still logs many data: I (114548) PacketHandler: spp_send_packet() D (114549) SendPacket: begin [00:01:54.549] ACL => 80 00 19 00 15 00 41 00 09 EF 20 00 41 02 30 30 30 31 32 3 0 35 36 2E 3...

I am currently trying to make btstack work. I am having some issues:
- how to switch off logging (in oder to increase speed)?
- sometimes the communication gets stuck for a few seconds; why?
- do you have some sample code?

I am also still waiting for the support of the SPP profile in esp-idf. Recently they published the ble_spp_server example but this does not help me because I need the real BT classic SPP profile. I found this ( https://github.com/bluekitchen/btstack/tree/master/port/esp32 ) solution, but unfortunate...