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Frequently Asked Questions / Troubleshooting

FAQ list 🔙

This Arduino library doesn't work on ESP. How do I make it working?

Introduction

You would like to use this Arduino library with ESP8266 and it doesn't perform. It is not listed among libraries verified to work with ESP8266. You couldn't find any evidence on internet that it is compatible.

What are the odds to make it working?

Identify the Issues

Start with looking for all the symptoms that it is not compatible with ESP8266. Ideally use example sketches provided with the library. Then list all the issues you are able to identify.

You are likely to see one or more of the following:

  • Compilation drops errors
  • There are no issues with compilation but application restarts because of exception or watchdog (wdt)
  • Application seems to work, but does not function as expected, e.g. calculation results are incorrect.

Armed with the list of issues, contact the library author asking for comments. If issues are legitimate, then ask for his / her support to implement it for ESP8266. Being specific you have bigger chances convincing the author to help you either by updating the library or guiding you how to resolve the issues.

Fix it Yourself

If library author is unable to provide support, then assess the chances of fixing it yourself.

Compilation Errors

Issue: Compiler complains about usage of AVR registers (PORTx, PINx, TCR1A, etc).

Solution: Check if usage of registers is well localized in a few functions, try to replace GPIO registers usage with digitalRead / digitalWrite, timer registers usage with timerX_ functions. If usage of AVR registers happens all over the code, this library might not be worth the effort. Also may be worth checking if someone got the library working on ARM (Due/STM), PIC, etc. If this is the case, maybe there already is a version of the library which uses Arduino APIs instead of raw registers.

Issue: Compiler complains about <avr/pgmspace.h>.

Solution: modify the library by adding conditional include of ESP's pgmspace.h.

#ifdef ESP8266
  #include <pgmspace.h>
#else
  #include <avr/pgmspace.h>
#endif

Exceptions / Watchdog Resets

To troubleshoot resets follow FAQ item My ESP crashes running some code.

Functionality Issues

Issue: Application works but returns weird numerical values.

Solution:: Check the usage of int type in the library. On AVRs integers are 16 bit, and on ESPs they are 32 bit (just like on ARM).

Issue: Some device with time critical control like a servo drive or a strip pf LEDs does not operate smoothly and tends to randomly change position or displayed pattern.

Solution:: Check for usage of interrupts that may get in conflict with Wi-Fi activity of ESP8266. You may temporarily disable Wi-Fi communication WiFi.mode(WIFI_OFF); to check if it helps.

Conclusion

Identify compatibility issues and ask library author for support. If left on your own, then check for usage of controller's low level access functionality. Use Esp Exception Decoder if confronted with exceptions / watchdogs resets.

The good news is that the number of libraries which aren't supported on the ESP8266 is shrinking. Community of ESP8266 enthusiasts is growing. If you are unable to resolve the issues yourself, there are very good odds that you will be able to find somebody else to help you.

FAQ list 🔙