An edited copy of PZEM-004T-V30 library from: https://github.com/mandulaj/PZEM-004T-v30
That is adapted to the SAMD21 processor.
Tested on ARDUINO NANO IOT 33.
zygisjas/PZEM-004T-V30-SAMD21
An edited copy of PZEM-004T-V30 library from: https://github.com/mandulaj/PZEM-004T-v30
C++