Level shifter for TTL?

[matthias-straub]

Hi Martin,

Great work, thank you. Did you connect the ESP (3.3V logic level) directly to X6 (5V logic level)? This might work if you're lucky, but it didn’t work for me when I tried. I wouldn’t be too worried about damaging the ESP8266; however, its 3.3V output doesn’t seem sufficient to drive the X6 line high.

Best regards
Matthias

[DrSpaltenstein]

Hi, I tried without level shifter (ESP32 + Ecovit VKK226 + VRC420). basically works, but after some time the heaters diagnostic shows connection error and shuts down all the pumps etc. Don't know if the logic level is the reason or if there is some conflict on th X6 bus when ESP and VRC start sending at the same time.