Switched to Official SDK

README.md

@@ -1,7 +1,9 @@
 # LYWSD03MMC 2025 B1.5 (pvvx B1.1) BTHome v2 beacon + LCD + OTA
 
 Port of the nRF52840/Zephyr SHT41 beacon to the Xiaomi LYWSD03MMC
-(Telink TLSR8251). Same behaviour:
+(Telink TLSR8251), built on the official Telink BLE SDK
+([tc_ble_single_sdk](https://github.com/telink-semi/tc_ble_single_sdk)
+V3.4.3.0). Same behaviour:
 
 - every 60 s: measure temperature/humidity, read the battery right after the
   sensor load, update the advertisement
@@ -12,8 +14,9 @@ Port of the nRF52840/Zephyr SHT41 beacon to the Xiaomi LYWSD03MMC
   it in the scan response only, as pvvx does)
 - a failed sensor read keeps advertising the last good T/RH; the voltage is
   updated on every measurement
-- Telink OTA service for over-the-air firmware updates, reachable only
-  during the first 2 minutes after the battery is inserted (see Flashing)
+- Telink OTA service (the SDK's OTA server) for over-the-air firmware
+  updates, reachable only during the first 2 minutes after the battery is
+  inserted (see Flashing)
 
 plus the display: temperature (0.1 °C, `°C`), humidity (`%`), battery icon
 below 2.4 V, `-- --` until the first good reading. The LCD controller holds
@@ -60,19 +63,53 @@ pvvx/ATC_MiThermometer.
 - The sensor is wired straight to the coin cell, so there is no power gating;
   the SHTV3 is put to sleep explicitly after every measurement.
 - Voltage is VDD (= CR2032), measured by driving the unbonded PB0 pad high
-  and sampling it with the ADC. Uses the typical 1175 mV reference, so expect
-  a few % absolute error; adjust `ADC_VREF_MV` against a meter if needed.
+  and sampling it with the ADC. The ADC reference is the chip's factory
+  calibration, which the SDK loads from the calibration sector or eFuse
+  (typical 1175 mV when there is none). To trim against a meter, set
+  `ADC_VREF_MV` to a fixed value in mV.
 
 ## Build
 
+Builds on Linux x86-64 only (the SDK's post-build tool is a Linux x86-64
+binary). Official Telink SDK, used unmodified, plus the TC32 toolchain:
+
 ```sh
-git clone https://github.com/pvvx/ATC_MiThermometer ../ATC_MiThermometer
+git clone -b release/V3.4.3.0 https://github.com/telink-semi/tc_ble_single_sdk ../tc_ble_single_sdk
+# apply the official patches as tc_ble_single_sdk_v3.4.3.0_Patch/patch_*/Patch_Guide.txt
+# says (copy each patch folder over tc_ble_single_sdk/, 0001 then 0002)
 # TC32 toolchain (Linux): e.g. https://github.com/flyskywhy/tc32 branch "linux"
-ln -s /path/to/tc32 ../ATC_MiThermometer/SDK/tools/linux/tc32
-make
+make TC32_PATH=/path/to/tc32/bin/
 ```
 
-Produces `LYWSD03MMC-BTHome.bin` (with the Telink CRC appended).
+`SDK_PATH` defaults to `../tc_ble_single_sdk/tc_ble_single_sdk`. The
+makefile uses the same compiler flags, startup code
+(`boot/B85/cstartup_825x.S`, `MCU_STARTUP_8251`: 32 KiB SRAM), linker
+script (`project/tlsr_tc32/B85/boot.link`), libraries (`lt_825x`,
+`lt_general_stack`) and post-build tool (`script/tl_check_fw/check_fw`)
+as the SDK's own `825x_ble_sample` project. Because the SDK only
+looks up `app_config.h` for its own demo projects, `src/app_config.h` is
+force-included (`-include`) into every file, SDK sources included.
+
+Produces `LYWSD03MMC-BTHome.bin` (with the Telink CRC appended) and prints
+the memory use: about 54 KiB of image, 17.8 KiB of RAM code + retained data
+(so 32 KiB deep-sleep retention, as before), 21 KiB of the 32 KiB SRAM.
+
+### Changes from the pvvx-SDK build
+
+- RF/clock bring-up, calibration loading
+  (`blc_app_loadCustomizedParameters_normal()` / `_deepRetn()`), retention
+  size selection and the OTA server API are the official ones.
+- The power-on marker moved from `DEEP_ANA_REG0` to `DEEP_ANA_REG1`: the
+  official SDK reserves bit 1 of `DEEP_ANA_REG0` for its crystal start-up
+  failure flag.
+- OTA: inactivity timeout 16 s (`OTA_PACKET_TIMEOUT_S`), whole upload at
+  most 1000 s (`OTA_PROCESS_TIMEOUT_S`; the SDK default would abort after
+  30 s); images up to 124 KiB (SDK limit). The OTA characteristic gained
+  NOTIFY and a CCC descriptor, as in the SDK sample, because the official
+  server answers the extended OTA protocol on it.
+- Flash write protection is still cleared once per power-on (status
+  register := 0, as pvvx), now with the SDK's flash driver and only when a
+  protection bit is set.
 
 ## Flashing
 
@@ -81,7 +118,7 @@ Produces `LYWSD03MMC-BTHome.bin` (with the Telink CRC appended).
   "Select Firmware" → custom file. Units running the previous build of this
   firmware (no OTA) need one wired flash: USB-UART adapter on the SWS pad,
   `TlsrComProg`/`ATCtelink.py` from the pvvx repo.
-- **Updates** (this firmware → any Telink image ≤ 128 KiB, including back to
+- **Updates** (this firmware → any Telink image ≤ 124 KiB, including back to
   pvvx or stock), with https://pvvx.github.io/ATC_MiThermometer/TelinkOTA.html:
   1. Take the battery out, wait ~5 s, put it back. The BLE symbol on the
      LCD means the OTA window is open: for 2 minutes the device accepts
@@ -97,12 +134,14 @@ Produces `LYWSD03MMC-BTHome.bin` (with the Telink CRC appended).
 
   The new image is written to the inactive flash bank and only activated
   after its CRC checks out, so an interrupted upload leaves the current
-  firmware running. The transfer aborts after 16 s without data.
+  firmware running. The transfer aborts after 16 s without data or after
+  1000 s in total.
 
   The window opens only on a real power cycle. Reboots without one
-  (low-battery sleep, OTA reboot, crash) keep it closed. After installing
-  this firmware by OTA from pvvx firmware, power-cycle once before the next
-  update.
+  (low-battery sleep, OTA reboot, crash) keep it closed. Exception: the
+  first boot after installing this build by OTA from other firmware (stock,
+  pvvx, or the earlier pvvx-SDK build of this firmware) opens the window
+  once, because the marker register was never set.
 
 **OTA itself is unauthenticated**: anyone in Bluetooth range can upload
 firmware while the window is open, so it is limited to 2 minutes after a