docs: Expand README for ssd1327 driver. (#218)

* docs: Expand README for ssd1327 driver.

* docs: Rewrite ssd1327 README addressing all review comments.

---------

Co-authored-by: Sébastien NEDJAR <sebastien@nedjar.com>

Author: Charly-sketch

lib/ssd1327/README.md

@@ -1,9 +1,123 @@
-# MicroPython library for SSD1327 128x128 4-bit greyscale OLED displays
+# SSD1327 MicroPython Driver
 
-This library is a port of the [MicroPython library for SSD1327 128x128 4-bit greyscale OLED displays](https://github.com/mcauser/micropython-ssd1327).
+MicroPython driver for the **SSD1327 128x128 4-bit greyscale OLED display controller**.
 
-The examples could be easily tested with [mpremote](https://docs.micropython.org/en/latest/reference/mpremote.html) with the following command :
+This library is a port of [micropython-ssd1327](https://github.com/mcauser/micropython-ssd1327).
 
-```sh
- mpremote mount . run examples/hello_world.py
+## Supported Display
+
+| Feature     | Value             |
+| ----------- | ----------------- |
+| Controller  | SSD1327           |
+| Resolution  | 128 × 128 pixels  |
+| Color depth | 4-bit (16 levels) |
+| Interfaces  | I²C, SPI          |
+| Default I²C address | `0x3C`   |
+
+## Features
+
+* 128x128 OLED display support
+* 4-bit greyscale (16 levels)
+* I²C and SPI interfaces
+* FrameBuffer-based rendering API
+* Drawing primitives: pixels, lines, text, scrolling
+* Display control: contrast, invert, rotation
+* Power management: display on/off
+
+## Basic Usage
+
+```python
+from machine import I2C
+from ssd1327 import WS_OLED_128X128_I2C
+
+i2c = I2C(1)
+display = WS_OLED_128X128_I2C(i2c)
+
+display.fill(0)
+display.text("Hello STeaMi", 0, 0)
+display.show()
+```
+
+## FrameBuffer Integration
+
+The driver extends `framebuf.FrameBuffer` and exposes the following drawing methods directly:
+
+* `fill(color)` — fill entire display
+* `pixel(x, y, color)` — set a single pixel
+* `line(x1, y1, x2, y2, color)` — draw a line
+* `text(string, x, y, color=15)` — render text
+* `scroll(dx, dy)` — scroll buffer contents
+
+Other FrameBuffer methods (`rect()`, `fill_rect()`, etc.) are accessible via `display.framebuf`.
+
+The buffer is stored in 4-bit greyscale format (GS4_HMSB). The internal buffer uses `width × height / 2` bytes (8192 bytes for 128×128). Call `show()` to push the buffer to the display.
+
+## API Reference
+
+### Initialization
+
+#### I2C (STeaMi board)
+
+```python
+from ssd1327 import WS_OLED_128X128_I2C
+
+display = WS_OLED_128X128_I2C(i2c, address=0x3C)
+```
+
+For custom resolutions:
+
+```python
+from ssd1327 import SSD1327_I2C
+
+display = SSD1327_I2C(width, height, i2c, address=0x3C)
+```
+
+#### SPI
+
+```python
+from ssd1327 import WS_OLED_128X128_SPI
+
+display = WS_OLED_128X128_SPI(spi, dc, res, cs)
+```
+
+**Note:** `SSD1327_SPI` (custom resolution) is available via `from ssd1327.device import SSD1327_SPI` but is not exported by the package by default.
+
+### Display Control
+
+* `show()` — push the framebuffer to the display (required after any drawing)
+* `contrast(value)` — set brightness (0–255)
+* `invert(enable)` — enable/disable display inversion
+* `rotate(enable)` — rotate display 180°
+
+### Power Management
+
+* `power_on()` — turn display on
+* `power_off()` — turn display off (low power mode)
+
+### SPI-only
+
+* `reset()` — hardware reset via the reset pin (SSD1327_SPI only)
+
+## Examples
+
+| File                  | Description                                          |
+| --------------------- | ---------------------------------------------------- |
+| `bitmap.py`           | Display a 16x15 smiley bitmap with greyscale shading |
+| `framebuf_lines.py`   | Draw diagonal lines across the screen                |
+| `framebuf_pixels.py`  | Plot individual pixels at various positions          |
+| `framebuf_rects.py`   | Draw rectangles using the FrameBuffer API            |
+| `framebuf_scroll.py`  | Scroll text horizontally across the display          |
+| `framebuf_text.py`    | Render text strings at different positions           |
+| `hello_world.py`      | Minimal "Hello World" display example                |
+| `illusion.py`         | Render an optical illusion pattern                   |
+| `invert.py`           | Toggle display inversion on and off                  |
+| `lookup_table.py`     | Display a greyscale gradient using all 16 levels     |
+| `micropython_logo.py` | Display the MicroPython logo as a bitmap             |
+| `random_pixels.py`    | Fill the screen with randomly placed pixels          |
+| `rotating_3d_cube.py` | Animate a rotating wireframe 3D cube                 |
+| `rotation.py`         | Demonstrate 180° display rotation                    |
+| `shades.py`           | Display 15 shades of grey as vertical bands          |
+
+```bash
+mpremote mount lib/ssd1327 run lib/ssd1327/examples/hello_world.py
 ```