FAQ
TL;DR: The TUYA PC473 meter uses a 24-bit HT7032 metering core talking over 4-wire SPI at ≤500 kHz, stores 2 MB of flash, and, as one tester notes, "OpenBeken will run but won't be much use" [Elektroda, divadiow, post #21263926] Why it matters: understanding the SPI link is the key roadblock to full local control.
Quick Facts
• Metering IC: HT7032/7038, 24-bit registers, ±2 000 000 000 range [Elektroda, p.kaczmarek2, post #21285031]
• Comms: 4-wire SPI, mode 0, max 500 kHz clock [Elektroda, p.kaczmarek2, post #21285031]
• Wi-Fi module: Tuya CB3S (BK7231N) with 2 MB flash [Elektroda, ipasitt, post #21263503]
• Reported DPs: 30 + covering voltage, current, PF, forward/reverse kWh [Elektroda, divadiow, post #21263559]
• Physical relay: 1-ch, 3-phase switch, rated 63 A (datasheet typical)
Is the PC473 really a TuyaMCU (UART) device?
No. Boot logs and dump show no UART-based TuyaMCU framing; instead, HT7032 connects to CB3S by SPI on four pins marked CLK, CS, DO, DI [Elektroda, ipasitt, post #21263124]
What stops OpenBeken from reading measurements?
OpenBeken lacks an HT7032 SPI driver. Until commands, register map, and timing are implemented, the firmware cannot pull voltage or energy data [Elektroda, p.kaczmarek2, post #21265401]
Which SPI parameters are confirmed?
Mode 0, 24-bit data words, addresses 0x00–0x7F, host holds CS low for the whole transaction, and timing delay ≥2 µs when CLK exceeds 500 kHz [Elektroda, p.kaczmarek2, post #21285031]
What address space does HT7032 expose?
The vendor sample code lists 128 readable/writeable registers; key ones include 0x10 (Voltage L1), 0x1A (Active Power L1) and 0x40 (Energy Accumulator) [Elektroda, divadiow, post #21280952]
Can I still flash the module after assembly?
Yes. Solder to CB3S pads GND, 3 V3, U0RXD, U0TXD; the case opens after removing two back screws, but the top/bottom latches snap easily [Elektroda, ipasitt, post #21261496]
How big is the factory firmware image?
Each OTA file is 1 024 KB; complete backup occupies 2 048 KB because of dual-bank storage [Elektroda, ipasitt, post #21263503]
What changes between firmware 1.0.5 and 1.0.10?
Version 1.0.10 adds the full DP list, modifies cloud endpoints, and bumps SDK to 40.02; size grows by 7 % [Elektroda, divadiow, post #21263559]
Is there a known workaround to get DP IDs without Tuya cloud?
Yes. Dumping CB3S flash reveals a JSON block labelled by s_id that holds every DP schema; no Internet needed once you have the binary [Elektroda, divadiow, post #21263559]
Edge-case: what can go wrong during teardown?
Users report brittle plastic catches; applying too much torque will shear them, leaving the enclosure loose on DIN-rail [Elektroda, ipasitt, post #21261496]
3-step: How do I capture SPI traffic?
- Clip a 4-channel logic analyser to CS, CLK, DO, DI.
- Set samplerate ≥2 MHz, trigger on CS ↓.
- Export traces, decode as SPI-24-bit to log register and data words.
Will sending a hardware sample speed development?
Yes. The maintainer accepted the offer to receive a unit for driver work [Elektroda, ipasitt, post #21266519]
How accurate is HT7032 measurement?
Vendor claims ±0.1 % FS over −40 °C to 85 °C, comparable to class 1 energy meters “HT703x Datasheet”.
