However, the data might be lost after power cycling the chip.ĮSP.getResetReason() returns a String containing the last reset reason in human readable format.ĮSP.getFreeHeap() returns the free heap size.ĮSP.getChipId() returns the ESP8266 chip ID as a 32-bit integer.ĮSP.getCoreVersion() returns a String containing the core version.ĮSP.getSdkVersion() returns the SDK version as a char.ĮSP.getCpuFreqMHz() returns the CPU frequency in MHz as an unsigned 8-bit integer.ĮSP.getSketchSize() returns the size of the current sketch as an unsigned 32-bit integer.ĮSP.getFreeSketchSpace() returns the free sketch space as an unsigned 32-bit integer.ĮSP.getSketchMD5() returns a lowercase String containing the MD5 of the current sketch.ĮSP.getFlashChipId() returns the flash chip ID as a 32-bit integer.ĮSP.getFlashChipSize() returns the flash chip size, in bytes, as seen by the SDK (may be less than actual size).ĮSP.getFlashChipRealSize() returns the real chip size, in bytes, based on the flash chip ID.ĮSP.getFlashChipSpeed(void) returns the flash chip frequency, in Hz.ĮSP.getCycleCount() returns the cpu instruction cycle count since start as an unsigned 32-bit. The stored data can be retained between deep sleep cycles. Total size of RTC user memory is 512 bytes, so offset + sizeof(data) shouldn’t exceed 512. (GPIO16 needs to be tied to RST to wake from deepSleep.)ĮSP.rtcUserMemoryWrite(offset, &data, sizeof(data)) and ESP.rtcUserMemoryRead(offset, &data, sizeof(data)) allow data to be stored in and retrieved from the RTC user memory of the chip respectively. mode is one of WAKE_RF_DEFAULT, WAKE_RFCAL, WAKE_NO_RFCAL, WAKE_RF_DISABLED.

Some ESP-specific APIs related to deep sleep, RTC and flash memories are available in the ESP object.ĮSP.deepSleep(microseconds, mode) will put the chip into deep sleep.

Esp8266 problem with wire library