June 14, 2026Digital IC Design

Memory Map Design: Best Practices and Conventions

Best practices for memory map planning in chip design, including address allocation strategy, reserved space, and access permission design.

Memory Map Design: Best Practices and Conventions

What is a Memory Map?

A Memory Map defines the address space allocation for each module in a chip design. It determines how the CPU/DMA accesses various peripherals and memory regions.

1. Address Alignment Principles

4KB alignment: Large memory blocks and peripherals should be at least 4KB aligned for MMU management
Register blocks: Typically 4KB or larger
FIFO buffers: Usually require large contiguous blocks

2. Reserved Space Strategy

code

0x0000_0000 - 0x0FFF_FFFF : Boot ROM       (256MB)
0x1000_0000 - 0x1FFF_FFFF : Peripheral A   (256MB)
0x2000_0000 - 0x2FFF_FFFF : Peripheral B   (256MB)
0x3000_0000 - 0x3FFF_FFFF : Reserved       (256MB)
0x4000_0000 - 0x7FFF_FFFF : DRAM           (1GB)

Reserve at least 25-50% space between peripherals for future expansion.

3. Access Permissions

| Type | Description | Use Case | |------|-------------|----------| | RW | Read-Write | Control registers | | RO | Read-Only | Status registers | | WO | Write-Only | Trigger registers | | R/W1C | Read/Write-1-Clear | Interrupt flags |

4. Version Management

Use version numbers: Memory Map docs should have version and revision history
Reserved fields: Leave unused bits in registers
Backward compatibility: New registers should go at the end of existing blocks

Use the ICHDL Memory Map Generator to generate address mapping tables online.