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mangavalkandClaude Opus 5.5 873bdcd23e Set up PlatformIO project for EL512.256-H on ESP32

PlatformIO skeleton (esp32dev, Arduino, Adafruit GFX) with a local EL512
library: EL512Panel (1 bpp framebuffer, two-bit-mode row encoder, I2S DMA
refresh stub) and EL512_GFX (Adafruit_GFX subclass). Adds a test sketch,
pin map, README with wiring and timing, and moves the datasheet to
docs/datasheet/.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

2026-10-05 21:00:42 +02:00

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Planar EL512.256-H on ESP32

Drive a Planar EL512.256-H (512 × 256, monochrome electroluminescent) panel from an ESP-WROOM-32 (classic ESP32), with an Adafruit GFX compatible driver so the usual drawing, text and font APIs work.

The panel has no frame memory and needs a continuous video stream. The ESP32's I2S0 peripheral in 8-bit parallel (LCD) mode streams a precomputed frame from DMA, so the CPU is free while the panel refreshes.

Status: project skeleton. Framebuffer, GFX layer and row encoder are in place; the I2S/DMA start-up (EL512Panel::startI2S()) is still a stub.

Hardware

ESP-WROOM-32 dev board (esp32dev)
Planar EL512.256-H, configured for two-bit parallel mode (mode jumper OFF, see datasheet)
Datasheet: docs/datasheet/EL512.256-H3 FRB.pdf
Check the panel's logic-level and supply requirements in the datasheet before wiring.

Wiring

Panel signal	Function	ESP32 GPIO	DMA byte bit
VCLK	Video clock (rising edge)	18	I2S clock
VID	Pixel data, even columns	19	0
TVID	Pixel data, odd columns (two-bit mode)	21	1
HS	Horizontal sync	22	2
VS	Vertical sync	23	3
ENABLE	Display enable	25	—
_LOWPWR	Low-power mode (active low)	26	—
GND	Ground	GND	—

The pin map lives in include/pins.h.

Timing

Parameter	Value
Pixel clock (VCLK)	5 MHz, 2 pixels per clock
Clocks per row	272 (256 data + 16 blanking)
Lines per frame	261 (256 visible + 5 blanking)
Refresh	5 MHz / (272 × 261) ≈ 70.4 Hz

Layout

platformio.ini        build config (esp32dev, Arduino, Adafruit GFX)
include/pins.h        pin map
src/main.cpp          test sketch: test pattern + text
lib/EL512/            local library
  src/EL512Panel.*    framebuffer, row encoder, I2S DMA refresh (stub)
  src/EL512_GFX.*     Adafruit_GFX subclass
test/                 unit tests (placeholder)
docs/                 datasheet and notes

Build and flash

Requires PlatformIO (CLI or the VS Code extension).

pio run

pio run -t upload

pio device monitor

Using the driver

#include <EL512.h>
#include "pins.h"

EL512Panel panel({el512pins::VCLK, el512pins::VID, el512pins::TVID, el512pins::HS,
                  el512pins::VS, el512pins::ENABLE, el512pins::LOWPWR_N});
EL512_GFX display(panel);

void setup() {
  display.begin();
  display.setTextColor(1);
  display.print("Hello");
  display.display();   // push the drawing buffer to the refresh stream
}

See docs/README.md for design notes and the plan.

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