ESP8266 ESP32 Compatibility

This document reflects conflicts between NodeMCU/ESP8266 and NodeMCU/ESP32 and requirements to achieve larger degree of compatibility:

adc

ESP8266:

• adc.force_init_mode(node) Checks and if necessary reconfigures the ADC mode setting in the ESP init data block.
  • mode:
    • adc.INIT_ADC
    • adc.INIT_VDD33
• adc.read() Samples the ADC.
• adc.readvdd33() Reads the system voltage.

ESP32:

• adc.setup(adc_number,channel,atten)
  • adc_number Only adc.ADC1 now
  • channel When using adc.ADC1: 0 to 7. 0: GPIO36, 1: GPIO37, 2: GPIO38, 3: GPIO39, 4: GPIO32, 5: GPIO33, 6: GPIO34, 7: GPIO35
  • atten One of following constants
    • adc.ATTEN_0db The input voltage of ADC will be reduced to about 1/1 (1.1V when VDD_A=3.3V)
    • adc.ATTEN_2_5db The input voltage of ADC will be reduced to about 1/1.34 (1.5V when VDD_A=3.3V)
    • adc.ATTEN_6db The input voltage of ADC will be reduced to about 1/2 (2.2V when VDD_A=3.3V)
    • adc.ATTEN_11db The input voltage of ADC will be reduced to about 1/3.6 (3.9V when VDD_A=3.3V, maximum voltage is limited by VDD_A)
• adc.read() Samples the ADC.

bit

bthci

can

dht

file

The object mode of file operations isn't implemented yet (file.read() vs src = file.open() src:read()) according dev-esp32 documentation.

ESP8266:

• file.obj:close() Closes the open file, if any.
• file.obj:flush() Flushes any pending writes to the file system, ensuring no data is lost on a restart.
• file.obj:read() Read content from the open file.
• file.obj:readline() Read the next line from the open file.
• file.obj:seek() Sets and gets the file position, measured from the beginning of the file, to the position given by offset plus a base specified by the string whence.
• file.obj:write() Write a string to the open file.
• file.obj:writeline() Write a string to the open file and append '\n' at the end.

ESP32:

• all above listed are missing according documentation

gpio

ESP8266:

• gpio.mode(pin,type,pullup)
  • type:
    • gpio.INPUT
    • gpio.OUTPUT
    • gpio.OPENDRAIN
    • gpio.INT
  • pullup:
    • gpio.FLOAT (default)
    • gpio.PULLUP enables the weak pull-up resistor
• gpio.trig(pin,type,callback(level,when))
  • type: "up", "down", "both", "low", "high"

ESP32:

• gpio.config({gpio=..,dir=..,pull=..,opendrain=..})

  • dir:
    • gpio.IN
    • gpio.OUT
    • gpio.IN_OUT
  • pull:
    • gpio.FLOATING disables both pull-up and -down
    • gpio.PULL_UP enables pull-up and disables pull-down
    • gpio.PULL_DOWN enables pull-down and disables pull-up
    • gpio.PULL_UP_DOWN enables both pull-up and -down

• gpio.trig(pin,types,callback(pin,level))

  • type:
    • gpio.INTR_UP for trigger on rising edge
    • gpio.INTR_DOWN for trigger on falling edge
    • gpio.INTR_UP_DOWN for trigger on both edges
    • gpio.INTR_LOW for trigger on low level
    • gpio.INTR_HIGH for trigger on high level

i2c

ledc

net

node

ESP8266:

• node.info() return 8 elements:

  • majorVer (number)
  • minorVer (number)
  • devVer (number)
  • chipid (number)
  • flashid (number)
  • flashsize (number)
  • flashmode (number)
  • flashspeed (number)

• node.chipid() returns an integer (last 3 bytes of the station MAC address)

ESP32:

• node.info() missing
• node.chipid() returns hex string with '0x' as prefix and 7 bytes whereas the last byte of the MAC address is dropped (risk of 256 identical chipids)

ow (1-Wire)

sdmmc

sigma delta

spi

struct

tmr

ESP8266:

• tmr.now() returns microseconds
• tmr.time() time in seconds since boot (uptime)

ESP32:

• tmr.now() missing
• tmr.time() missing

u8g2

u8g2 Display

uart

wifi

ESP8266 and ESP32 differ a lot:

ESP8266

• events are captured via wifi.eventmon.*:
  • wifi.eventmon.register(event[, function(T)])
    • wifi.eventmon.STA_CONNECTED
    • wifi.eventmon.STA_DISCONNECTED
    • wifi.eventmon.STA_AUTHMODE_CHANGE
    • wifi.eventmon.STA_GOT_IP
    • wifi.eventmon.STA_DHCP_TIMEOUT
    • wifi.eventmon.AP_STACONNECTED
    • wifi.eventmon.AP_STADISCONNECTED
    • wifi.eventmon.AP_PROBEREQRECVED

ESP32:

• events are captured via wifi.on()
  • wifi.ap.on(event, callback)
    • event:
      • start: no additional info
      • stop: no additional info
      • sta_connected: information about the client that connected:
      • mac: the MAC address
      • id: assigned station id (AID)
      • disconnected: information about disconnecting client
      • mac: the MAC address
      • probe_req: information about the probing client
      • from: MAC address of the probing client
      • rssi: Received Signal Strength Indicator value

ws2812