Tuya WiFi Energy Meter PM01_A002 [CBU][BK7231N] HLW8112 SPI Power Reading Ratio 1:5?

I'll start a dedicated thread for this device.

In another thread, a similar power meter is covered, but there'are mixed messages referring
both devices, causing a little bit of confusion. (https://www.elektroda.com/rtvforum/topic4016609.html)

The device I'll cover in this thread is the following:

      

Bough from Aliexpress: https://it.aliexpress.com/item/1005007292927857.html

What are my findings:

- HLW8112 (https://redmine.laas.fr/attachments/download/3444/DS_HLW8110_HLW8112_EN_Rev1.01%20.pdf)
- Unstable firmware (at least in my device)
- Power MeterIC connected directly to CBU module via SPI (NO TuyaMCU)
- Backup and restore firmware causes wrong measurement, but subsequently I discovered that all power values are reported in a ratio 1:5

By reading the posts from the other thread I concluded that there is no way to use TuyaMCU driver because the Power Meter IC
is directly connected to the Tuya module via SPI.

In fact @dicamarques made an attempt to write a driver for it (21221637#21221637), but, at least with my device,
by compiling the code he wrote from his GitHub repo, I was unable to get SPI working.

Furthermore Dicamarques and other guys posted a lot of useful informations:
- a schematc where you can see that P9 is used for "SCSN"  instead of the standard P15.
- links where very complete and presumably working drivers can be found

Subsequently I wanted to try to write my own driver... 
Spoiler  I wrote a lot of code, half of it, copy/pasted from the full driver source from the link above, but with no luck... the SPI still not send or receive data.

This i the link to my repo, in case someone more experienced can tell me what I'm doing wrong  https://github.com/kaleidoscopeit/OpenBK7231T_App_HLW8112
(--> To start the driver, issue "startDriver HLW8112SPI" in the command field of the log console in the Web Application)

It could be that I'm doing something crazy, like buying a logic analyzer and connect it to the SPI in order to understand what goin on when
the original Tuya firmware speaks with the Power Meter IC.

I thank the guys who posted in the other thread and I invite everyone to continue in this one.

Interesting, have you seen BL0942 SPI driver in our repository? Maybe it could serve as a reference.

Hi, yes I used it in order to build the base structure and get useful hints on how to write a driver. Thank you.

I've updated the main topic message with the link to my fork of OpenBK7231T_App.

I think you should start with the most basic transmit and read code. Try to choose some register from HLW datasheet and then try to read it with OBK.