Fixed-outline packing

An IoT microcontroller on a tall, narrow fixed outline packed with 25 macros - caches and memories, the CPU and its accelerators (AES, SHA, TRNG, FPU), DMA engines, and a full set of peripherals. The die is deliberately small and far taller than it is wide, so at this block count simply fitting everything legally is the hard part.

• Legality - all 25 macros inside the tall core with a halo. The narrow width fits only a couple of blocks across, so every loose macro eats room the next one needs. Pack in columns, largest blocks first.
• Timing closed - critical nets under budget: the sram0 to the flash interface, the cpu to the AHB bus and its caches, the regs to the clock, and the dma0 to the APB bus.
• No congestion overflow - a slim, dense die crowds its routing easily, so watch the demand map as you pack.

Drag, Run analysis, Place & Route, Submit.