Build and push server image / build-and-push (push) Successful in 32s
Back button (new GPIO0, POST /frame/back): the server now tracks a bounded history of previously-current photos (photo_queue.py), pushed to on every advance (auto or forced) and popped by back_forced() -- symmetric with advance, so pressing next afterwards returns to right where you were. frame_client.c's force_advance bool becomes a 3-way fetch_action_t (NORMAL/ADVANCE/BACK) threaded through the whole fetch path. Also folds the separate reset and manage buttons onto one pin (combo_button.c, replacing reset_button.c/manage_button.c entirely), disambiguated by hold duration: quick press shows the management menu (unchanged), ~3s hold-then-release soft-resets (esp_restart(), config kept -- new), ~15s hold factory-resets (today's old reset behavior, extended from 10s for clearer tier separation). Driven by a production board (Seeed XIAO ESP32-C6) exposing only 3 of the ESP32-C6's 8 deep-sleep-wakeup-capable GPIOs -- next/back keep their own dedicated pins where instant response matters most, everything else shares the third pin via timing instead of needing its own. Same three-pin layout now works on both the dev board and the production board. Fixed a fast-tap bug in combo_button_check() before shipping: it only did a live gpio_get_level() read to decide whether the button was pressed at all, so a press fast enough to already be released by the time boot reached that check was missed entirely (treated as "never pressed" rather than "quick press"). Added the same latched esp_sleep_get_gpio_wakeup_status() check the other buttons already use for exactly this reason.
83 lines
4.0 KiB
Markdown
83 lines
4.0 KiB
Markdown
# Hardware
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## Parts
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- An ESP32-C6 dev board (e.g. ESP32-C6-DevKitC-1). Needs 8MB flash --
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see [`firmware/sdkconfig.defaults`](../firmware/sdkconfig.defaults) and
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[`firmware/partitions.csv`](../firmware/partitions.csv) if yours differs.
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- [Waveshare 7.3" E Ink Spectra 6 (E6) panel](https://www.waveshare.com/7.3inch-e-paper-hat-e.htm) --
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800x480, 6-color, SPI.
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- A USB cable for flashing/power.
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## Wiring
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The panel connects over SPI plus three control lines (data/command, reset,
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busy). Defaults below match the reference build and are set in
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[`firmware/components/epd7in3e/Kconfig`](../firmware/components/epd7in3e/Kconfig) --
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override via `idf.py menuconfig` under **E-Paper Display (epd7in3e)
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Configuration** if your wiring differs.
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| Panel pin | ESP32-C6 GPIO | Kconfig option |
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| --------- | ------------- | ----------------- |
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| CLK | 20 | `EPD_PIN_CLK` |
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| DIN | 19 | `EPD_PIN_MOSI` |
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| CS | 18 | `EPD_PIN_CS` |
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| DC | 9 | `EPD_PIN_DC` |
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| RST | 10 | `EPD_PIN_RST` |
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| BUSY | 11 | `EPD_PIN_BUSY` |
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| VCC | 3.3V | -- |
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| GND | GND | -- |
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Optionally, three buttons, all wired the same way -- momentary push button
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between the GPIO and GND, no external resistor needed (the firmware
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enables each pin's internal pull-up, so it idles high and reads low when
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pressed):
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- **Next photo (GPIO2)**: a normal press skips immediately to the next
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photo; see
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[`firmware/README.md`](../firmware/README.md#skipping-to-the-next-photo).
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- **Back photo (GPIO0)**: a normal press returns to the previously-shown
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photo; see
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[`firmware/README.md`](../firmware/README.md#going-back-to-the-previous-photo).
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- **Menu / reset (GPIO1)**: one button, three actions by hold duration --
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a quick press overlays a "scan to manage" QR code on the current photo
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for 30 seconds; holding ~3s then releasing soft-resets the device
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(config kept); holding ~15s factory-resets it (clears WiFi/server
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config, reprovisions); see
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[`firmware/README.md`](../firmware/README.md#managing-the-queue-soft-resetting-and-factory-resetting).
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All three pins were picked because they're within GPIO 0-7 -- the only
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pins the ESP32-C6 can wake from deep sleep on -- aren't strapping pins,
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and aren't already used by the panel wiring above. Also, not
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incidentally, GPIO 0-7 is *all* the deep-sleep-wakeup-capable pins this
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chip has (`SOC_RTCIO_PIN_COUNT` is 8) -- worth knowing if you're
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targeting a compact board like the Seeed XIAO ESP32-C6, which only
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breaks out 3 of them (GPIO0/1/2). These three buttons were deliberately
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designed to fit exactly that budget: two dedicated pins for the
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actions where instant, unambiguous response matters most (next, back),
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and everything else folded onto the third pin via hold duration instead
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of needing its own pin.
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A couple of things worth knowing if you pick different pins:
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- **Avoid the ESP32-C6's strapping pins** (GPIO 4, 5, 8, 9, 15) and the
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USB-JTAG pins (12, 13) where possible -- strapping pins are sampled at
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reset to select boot mode. The reference wiring above already uses
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GPIO9 for DC, which *is* a strapping pin; it's only sampled during
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power-on/reset, so it's safe once the app is running, but if
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flashing/boot ever misbehaves on your board, check whether the panel is
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pulling that line low during reset.
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- The panel's SPI interface is rated well above the firmware's default
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4MHz clock (`EPD_SPI_CLOCK_HZ`), but breadboard/dupont-wire connections
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are often unreliable much past a few MHz. Raise it once your physical
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wiring is confirmed solid.
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## Power
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The device spends nearly all its time in deep sleep, waking briefly once
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an hour (configurable, see the server's web UI) to fetch and display a
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photo. A full-color refresh on this panel takes 15-30+ seconds and draws
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more current than deep sleep by a wide margin -- expect battery life (if
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not running from USB power) to be dominated by refresh frequency, not
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sleep current.
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