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thermostat-hw/TODO.md
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mattandClaude ea1b8b8d15 Two indoor sensors, wind compass, and stop framebuffer cache thrashing
Downstairs and upstairs are now separate readings. The station names them
backwards -- "temperature_4" is downstairs and "inside_temperature" is
upstairs -- so ha_config.h says which is which. Downstairs is the primary:
big number on the card, and it is what the furnace controls on, because it
is where people are and heat rises. Upstairs sits beside it, obviously
subordinate by size, and costs no vertical space in a layout that has none.

The anemometer came back on 2026-08-07, so wind gets its own column: a dial
whose needle points at the direction the wind is coming FROM (weather-vane
convention, matching the cardinal below it), the speed, and a 5-minute trend
arrow.

  - The needle does not animate. A spin would look better, but every animated
    frame is a redraw, and redrawing is what starves the bounce refill ISR.
  - Below 0.5 mph it shows "Calm" and draws no needle. A vane that is not
    being pushed reports whatever it last settled on, which on this station
    is a steady 0 degrees -- a confident needle pointing due north at zero
    wind. The live snapshot caught exactly that.
  - The trend is local, not HA's 10-minute average, so the window is ours to
    pick: 1-minute buckets over 5 minutes, threshold 1.5 mph.

That last point needed the trend engine to stop assuming one hour. Window,
bucket size, minimum age and threshold are now per-channel in a table, which
also removes the threshold arguments main.c was passing in.

Grid drops to 117px cells to make room, so the sun sub-line is just which
event it is and "RAIN TODAY" is "RAIN" -- both were overrunning.

On the artefacts: bounce mode is NOT a DMA read of the framebuffer. The
refill is a CPU memcpy in an ISR, which is why the driver skips the usual
write-back in draw_bitmap ("the data gets read by the CPU as well"). So the
panel streams 750KB per frame at ~44Hz through the DCache, evicting the
working set of everything else on the chip, continuously -- which is the real
reason this board is so sensitive to WiFi and to any extra rendering.
bb_invalidate_cache frees each chunk after it is copied. The header warns it
"can be dangerous if data is written from other core(s)"; that does not apply
here, because it invalidates the buffer being scanned and by design LVGL only
draws into the other one. Whether it is enough is for the panel to say.

Also gives tools/ha_snapshot.py a --token-file so the token no longer has to
travel through a shell command line to reach it.

Co-Authored-By: Claude <noreply@anthropic.com>
2026-08-07 19:58:41 -07:00

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6.3 KiB
Markdown

# TODO
## Thermostat: next steps
1. **Fit the relay board.** Wiring is in README "UART1-OUT plug". Until then
the GPIOs are the only output — meter them (idle reads 3.3 V, energized
0 V) to confirm the control loop end to end.
2. **Local temperature sensor.** The single biggest weakness: indoor temp
comes from HA over the network, so an HA outage eventually forces heat off.
An SHT30/BME280 on the I2C bus fixes it. Mount it away from the panel,
which self-heats by several degrees.
3. **Persist the setpoint.** Resets to 68 °F on every boot. NVS is not an
option while the panel scans (cache fault); an HA `input_number` is.
4. **Watchdog.** If the firmware hangs mid-call the relay stays latched until
someone notices. The furnace's own high limit makes that uncomfortable
rather than dangerous, but the task watchdog should reboot into the safe
state.
## Not yet verified on hardware
Flashed and booting clean (two-phase display init, icons on, first poll ~9s,
no errors), but eyes and fingers haven't confirmed:
1. Slider feel: press sends one command at the touch position immediately,
drag is display-only tracking the finger, lift sends the final level.
Poll data never moves a pressed knob.
2. Trend arrows appear ~5 minutes after boot (indoor big card, outdoor and
pressure cells) once the local ring has history. They are local-history
based and reset on reboot — that is by design, not a bug.
3. Artefact lifetime. Two "repaint to clean up" mitigations were tried and
both made it worse -- see README Gotchas. They are gone, the 1Hz restyle
that made the artefacts permanent is fixed, and the bounce buffer is up to
20 scanlines. If lines still come and go, the remaining honest levers are
fewer redraws still, less WiFi interrupt load during rendering, or 120MHz
PSRAM on a newer IDF.
## Done
The six items from the 2026-08-03 review were completed in `d4b2ab7`
("Work through the remaining review items in TODO.md"). See that commit
message for the reasoning behind each. Summary:
1. **UI pause window shrunk** — HTTP session kept alive between polls, timeout
drops 30s→10s once warm. Measured on hardware: fetch went from ~1.3s to
~80ms, so `lvgl_port_pause()` no longer blocks rendering and touch for a
meaningful period.
2. **Stale readings indicated** — temperature dims and the status line shows
age after two consecutive failures.
3. **Touch readout gated** behind `UI_DEBUG_TOUCH`, default off.
4. **`main/utils` deleted** — no callers.
5. **OTA partitions laid out** — two 4MB slots, `otadata`, ~7.9MB unallocated.
6. **Cleanups** — truncation logged once per response; weather task stack
high-water mark measured (~2400 bytes spare of 6144).
Verified on hardware after the change: boots from the new OTA layout, three
consecutive successful polls at 60s, no reboots.
## Still open
### 1. Confirm the left-edge artefacts are actually gone
The pause window is now ~80ms instead of ~1.3s, which should make the
artefacts much rarer — but **this has not been confirmed by eye**. The
timing improvement was measured from the log; the artefacts can only be
verified by watching the panel around the moment the status line updates.
If they persist, the remaining lever is pausing only around LVGL's flush (the
actual PSRAM writes) rather than the whole network transaction. That is more
invasive; do not start it until the current change has been observed to be
insufficient.
### 2. OTA implementation
Partition layout exists; the download/apply logic does not. **This is not a
drop-in.** An OTA write is a flash write, and the bounce-buffer refill ISR
reads PSRAM, which shares the cache with flash on the S3 — downloading while
the panel scans will fault it with "Cache disabled but cached memory region
accessed". The implementation must stop the panel for the download and write,
or reboot into a dedicated updater mode. See README "Partitions".
### 3. Backlight control (optional feature)
`backlight_set()` is only ever called once, with 255. A night-dim schedule or
touch-to-wake is a natural small feature. Note the STC8H1K28 shares the I2C
bus with the GT911, so brightness writes must stay in task context (never an
ISR) and will contend with touch polls on the same bus.
### 4. Left-edge artefacts, still open
Three things have been tried. Two "repaint to clean up" mitigations made it
worse and are gone (README Gotchas). The 1Hz restyle that made them permanent
is fixed. Now: bounce buffer at 20 scanlines and `bb_invalidate_cache` on, so
framebuffer streaming no longer thrashes the DCache.
If they persist after that, the mechanism is the raw PSRAM ceiling and the
honest remaining levers are unattractive: 120MHz PSRAM (needs a newer IDF and
a DC-aware bootloader), or a lower pixel clock (below ~15MHz the panel stops
locking and the image rolls). Do not reach for another repaint.
### 5. The actual thermostat
Setpoint, HVAC relay control, scheduling and persistence are all still
unimplemented — this remains a weather display. Note a separate project
(`~/workspace/rotaryThermo`) has a PRD for building this on the CrowPanel 2.1"
rotary display instead, driven by Zigbee room sensors. Decide which board
hosts the thermostat before building it twice.
## Facts already established — do not re-investigate
- Build is clean on ESP-IDF v5.3 (`. ~/esp/esp-idf/export.sh && idf.py build`).
App is ~1.4MB in a 4MB OTA slot.
- `main/app_config.h` is gitignored and holds real credentials locally.
- `resp_buf` bounds/NUL-termination in `ambient_weather.c` is correct.
- GT911 read-then-clear-status ordering is correct.
- Backlight duty inversion maps correctly at both endpoints (255→0x00 full,
0→0xF5 off).
- The `°` glyph exists in LVGL's built-in Montserrat fonts; the `·` separator
that does not appears only in log strings, never on screen.
- LVGL recursive-mutex locking is consistent across all UI entry points.
- Init order in `main.c` is deliberate and load-bearing:
`display_alloc()` before WiFi (contiguous bounce buffers from a virgin
heap), WiFi/NVS before `display_start()` (flash writes finished before
scan-out), `backlight_init()` before `touch_init()`. Never reorder.
- The bounce buffer is enabled and load-bearing.
- Board is N16R8 (16MB flash / 8MB octal PSRAM).
- `touch_get_indev()`, `display_get_panel()` and `lvgl_port_is_paused()` are
uncalled but deliberately kept as driver API surface.