Hierarchy

Top-Level

The top-level block is the DUT selected by a target. It provides the root address space and owns shared pins, timing, and services. The active instance is exposed as origen.dut.

Use the common DUT block for resources shared by all derivatives and place device-specific changes below blocks/dut/derivatives/<name>/. This avoids copying complete models for closely related products.

SubBlocks

Declare child instances in sub_blocks.py with SubBlock:

SubBlock("core0", "core")
SubBlock("core1", "core", offset=0x1000_0000)
SubBlock("adc", "adc.16_bit", offset=0x2000_0000)

The first argument is the instance name. The second identifies the block model. An optional offset relocates the child’s local address space in its parent. The same block model can therefore be instantiated multiple times at different addresses.

Plugin Blocks

Prefix the block path with a plugin package to instantiate reusable content:

SubBlock("dac", "company_common.dac", offset=0x8000_0000)

Some reusable services expose a class name or options:

SubBlock(
    "ram",
    "origen.memories",
    class_name="RAM",
    offset=0x1_0000,
    sb_options={"length": 0x1000},
)

Paths And Addressing

Resources are addressed through their instance path, for example dut.core1.adc0. A register’s absolute address is derived from its local address plus all parent offsets. Keep the register definition local to its block; do not bake a particular instance offset into reusable register source.

Controllers

Register writes and verifies flow through block controllers. A child controller normally forwards a request to its parent until a controller implements the transport, such as JTAG, SWD, or a memory access port. This lets one register model work with different access strategies.

Validation Checklist

Test at least one instance path and absolute address for every reusable block, especially when the same model is instantiated more than once. Also test plugin availability and required sb_options so missing dependencies fail early.