modelI2cGroveLcdRgb

Information

Twin of the Seeed Studio Grove - LCD RGB Backlight module: a 16x2 character screen whose backlight changes colour. The module carries two chips on the same I2C bus, hence two addresses for a single component:

• 0x3E — JHD1313, HD44780-compatible display controller: each byte is preceded by a control byte (0x80: command, 0x40: character). Emulated commands: clear, return home, entry mode, display on/off, shift, function set, write position (line 1 at 0x00, line 2 at 0x40).
• 0x62 — PCA9633, 4-channel LED driver: MODE1/MODE2 registers, PWM0–PWM3 brightnesses (blue, green, red), group dimming, LEDOUT; auto-increment register pointer.

The behaviour is entirely described by Resources/Scripts/Device/grove_lcd_rgb.py, which follows the datasheets of both chips without knowing anything about the program driving them: a driver written for the real module works unchanged — see Examples.I2c.GroveLcd, which runs an off-the-shelf MicroPython driver without modification. Like the real controller, the screen is off at power-up and the backlight black: the program has to initialise them. A byte sent during a clear (1.52 ms) is ignored, with a warning in the log — on the real module, it would be lost.

The pull-up resistors of the bus are enabled (usePullUp = true), as on the real module. valueOut: red, green, blue intensities (0-255) and screen on (1/0); the icon takes this colour and shows the two visible lines while replaying a result with animation in OMEdit.

Hardware note: recent revisions of the module (v5) replace the PCA9633 with another LED driver, at another address. This component follows the PCA9633 at 0x62, which the reference driver targets; the address can still be changed through addresses (the script treats 0x3E as the screen and any other address as the LED driver).

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