Flipdot-display/src/nano/README.md

Arduino Nano: flipdot driver

PlatformIO environment: nano

The Nano is connected directly to the Brose panel electronics. It keeps an 84 × 19 frame buffer and takes drawing commands over serial (115200 baud). It has no clock or network logic.

Behaviour

• Boot: the Nano flips the whole display on and then off, then prints the time a full redraw took.
• display(): compares the new buffer with the last one that was shown and strobes only the dots that changed.
• Every 2 minutes (REFRESH_TIME) it forces a full redraw to fix dots that got stuck.
• Flip pulse length (µs) is set with the T command and stored in EEPROM, so it is kept after a reboot.

Serial protocol

Each command is one ASCII line. Coordinates are 2-digit hex. Color is 0 (black) or 1 (yellow). The ESP32 driver (ESPSERIAL) only uses s, S, F, D and T.

Cmd	Format	Meaning
s	sXXYYc	Set pixel in the buffer
S	SXXYYc	Set pixel and flip it right away (direct mode)
F	Fc	Fill the whole buffer
D	D	Push the buffer to the display (changed dots only)
P	PXXYYcsTEXT	Print text at (XX,YY), color c, size s. \n in TEXT starts a new line.
B	BXXYYWWHHcHEX...	Draw a bitmap. WW must be a multiple of 4. Pixel data is one hex digit per 4 pixels.
R	R	Print the buffer as ASCII art on the serial port
T	Tnnn	Set the flip pulse length in µs (decimal), stored in EEPROM

Example (what the ESP32 sends for one pixel and a refresh):

s0a051
D

Wiring (default pinout)

The pins are defined in lib/BROSE9323/BROSE9323.h. If you use the PLCC adapter board, build with -D FLIPDOT_PLCC_ADAPTER to switch to its pinout.

Signal	Nano pin
ENABLE	D7
ADDR_0 / 1 / 2 (panel select)	D3 / D5 / D6
COL_DATA	D4
COL_0 … COL_4	D8, D10, D9, D11, D12
ROW_0 … ROW_4	A3, A4, A2, A0, A1
ROW_RESET	D13
ROW_SET	A5
Serial RX	D0 (from ESP32 TX)