Hardware:

Board: ESP32-DevKitC
Core Installation/update date: 9/6/2017
IDE name: Tested with platformio stage and "stable"

Description:

If the first attempt mounting an SD card via SD.begin() fails for some reason (such as the SPI bus is disconnected), subsequent calls crash the board. I suspect something is either not getting cleaned up or is getting cleaned up incorrectly when the mount fails.

If the card mounts successfully, I can run SD.end() and then SD.begin() as many times as I like without issue.

Sketch:

You can reproduce this by running the sketch below while not having an SD card reader attached.

#include <Arduino.h> #include <SD.h> void setup() { Serial.begin(115200); } void init_sd() { if(!SD.begin()){ Serial.println("Card Mount Failed"); return; } } void loop() { Serial.println("First attempt, will fail."); init_sd(); delay(5000); Serial.println("Second attempt, will crash the board."); init_sd(); // boom }

Debug Messages:

First attempt, will fail. [E][sd_diskio.cpp:739] sdcard_mount(): f_mount failed 0x(3) Card Mount Failed Second attempt, will crash the board. /Users/ficeto/Desktop/ESP32/ESP32/esp-idf-public/components/freertos/./queue.c:1792 (vQueueDelete)- assert failed! abort() was called at PC 0x40084a97 on core 1 Backtrace: 0x40087010:0x3ffccb40 0x4008710f:0x3ffccb60 0x40084a97:0x3ffccb80 0x400fbf21:0x3ffccba0 0x400fa7c2:0x3ffccbc0 0x400f134a:0x3ffccc00 0x400f079d:0x3ffccc30 0x400d0a39:0x3ffccc60 0x400d0a6b:0x3ffccc80 0x400f21d5:0x3ffccca0 Rebooting... ets Jun 8 2016 00:22:57 

Stacktrace:

No extra info seems to show up with debug on, but I've attached a decoded but not particularly helpful stacktrace:

0x00000bac: ?? ??:0 0x400fa7c2: f_mount at ff.c:4443 0x3ffccc80: ?? ??:0 

Thanks for all your awesome work and let me know if I can provide any additional information.