//! Bitplane-oriented framebuffer implementations for HUB75 LED panels.
//!
//! These framebuffers store colour data as one bit-plane per colour bit
//! (typically 8 planes for full 8-bit colour). To render, configure the DMA
//! descriptor chain to output each plane `2^(7 - plane_index)` times so that
//! the weighted repetition counts produce correct BCM brightness.
//!
//! Two variants are provided:
//!
//! - [`plain`] -- 16-bit entries with all signals (address, latch, OE, colour)
//! packed into each word. No external latch circuit needed.
//! - [`latched`] -- 8-bit entries with separate address bytes, requiring an
//! external latch circuit but halving per-entry memory.