Public Access
mangavalkandClaude Opus 5.5
6e4d5e152b
Nano / driver: - No full on/off flip at boot; the first display() after boot is a forced full redraw instead, since the physical dot state is unknown - Send READY when booted ESP32: - relayOn() only switches and waits when the relay was off, and waits for the Nano's READY (3 s timeout) instead of a fixed 3 s on every frame - relayOff() ends Serial and releases the TX pin so the idle-high line no longer back-powers the Nano through its RX pin - No display commands are sent while the relay is off - Switching the relay on cancels a pending power-off countdown Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
81 lines
3.3 KiB
Markdown
81 lines
3.3 KiB
Markdown
# Arduino Nano: flipdot driver
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PlatformIO environment: `nano`
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The Nano is connected directly to the Brose panel electronics. It keeps an 84 × 19 frame
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buffer and takes drawing commands over serial (115200 baud). It has no clock or network
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logic.
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## Behaviour
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- **Boot:** the Nano loads the flip time from EEPROM, sets up the pins and sends `READY`.
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It doesn't flip any dots at boot. The relay powers the Nano, so it boots every time the
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display is switched on.
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- **First `display()` after boot** redraws every dot, because the Nano doesn't know which
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state the dots were left in.
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- **`display()`:** compares the new buffer with the last one that was shown and strobes
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only the dots that changed.
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- **Every 2 minutes** (`REFRESH_TIME`) it does a full redraw to fix dots that got stuck.
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A full redraw blocks for about half a second, which is long enough to overflow the
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64-byte serial buffer. So it only runs right after a `D` (the end of a frame, when the
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ESP is quiet) or when no serial data has arrived for 2 seconds.
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- **Flip pulse length** (µs, 50–2000) is set with the `T` command and stored in EEPROM,
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so it is kept after a reboot. The default is 200 µs.
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### Debug options
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Uncomment these at the top of `main.cpp`:
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| Define | Effect |
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|--------|--------|
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| `DEBUG` | Print unknown command bytes on the serial port |
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| `MEASURE_REFRESH` | At boot, time a full redraw and print the duration in ms |
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## Serial protocol
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Each command is one ASCII line that **ends with `\n`** (`\r` is ignored). The Nano
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collects a whole line before it runs the command. If a line is broken or unknown, it is
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skipped and the next line starts clean. Coordinates are 2-digit **hex**. Color is `0`
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(black) or `1` (yellow). The ESP32 driver (`ESPSERIAL`) only uses `s`, `S`, `F`, `D` and
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`T`.
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| Cmd | Format | Meaning |
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|-----|--------|---------|
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| `s` | `sXXYYc` | Set pixel in the buffer |
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| `S` | `SXXYYc` | Set pixel and flip it right away (direct mode) |
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| `F` | `Fc` | Fill the whole buffer |
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| `D` | `D` | Push the buffer to the display (changed dots only) |
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| `P` | `PXXYYcsTEXT` | Print text at (XX,YY), color `c`, size `s`. A literal `\n` (backslash, n) in TEXT starts a new line. The whole line can be at most 64 characters. |
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| `B` | `BXXYYWWHHcHEX...` | Draw a bitmap. WW must be a multiple of 4. Pixel data is one hex digit per 4 pixels, row by row. The data is drawn while it arrives, so it is not limited to 64 characters. |
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| `R` | `R` | Print the buffer as ASCII art on the serial port |
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| `T` | `Tnnn` | Set the flip pulse length in µs (decimal, 50–2000), stored in EEPROM |
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Replies on the Nano's TX pin:
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- `READY` after booting. The ESP waits for it before sending the first frame.
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- `ERR: ...` for invalid commands.
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Example (what the ESP32 sends for one pixel and a refresh):
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```
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s0a051
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D
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```
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## Wiring (default pinout)
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The pins are defined in [lib/BROSE9323/BROSE9323.h](../../lib/BROSE9323/BROSE9323.h).
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If you use the PLCC adapter board, build with `-D FLIPDOT_PLCC_ADAPTER` to switch to its
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pinout.
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| Signal | Nano pin |
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|--------|----------|
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| ENABLE | D7 |
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| ADDR_0 / 1 / 2 (panel select) | D3 / D5 / D6 |
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| COL_DATA | D4 |
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| COL_0 … COL_4 | D8, D10, D9, D11, D12 |
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| ROW_0 … ROW_4 | A3, A4, A2, A0, A1 |
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| ROW_RESET | D13 |
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| ROW_SET | A5 |
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| Serial RX | D0 (from ESP32 TX) |
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