Snitch Cluster

This ip contains a cluster of Snitch cores, arranged in a specific (but configurable fashion).

Memory Map

The memory map of the cluster is determined by the cluster_base_addr_i signal. Depending on the amount of memory the TCDM and Periph regions will be scaled accordingly. The peripheral region will always be the same size as the TCDM.

Let TCDMSize denote the size of the TCDM.
Let PeripheralSize denote the size of the cluster peripheral address space.
Let TCDMEndAddress = cluster_base_addr_i + TCDMSize
Let SocEndAddress = TCDMEndAddress + PeripheralSize

Range	Dest	Description
[`SocEndAddress` - )	SoC	Routed out of the cluster. Address range depends on available address bits.
[`TCDMEndAddress` - `SocEndAddress`)	Periph	Cluster local peripherals.
[`cluster_base_addr_i` - `TCDMEndAddress`)	TCDM	Cluster local tightly coupled data memory.
[`0x0` - `cluster_base_addr_i`)	SoC	Routed out of the cluster.

Info

Because the address check on each core's LSU path is quite critical, we rely on a simplified checking scheme were we revert to checking the address against a mask and base combination. This makes the hardware less expensive (and faster) as no complicated adder circuits are needed and a couple of and gates are enough. (In comparison to a full address check where two adders are need)

assign match = (addr_base & addr_mask) == (addr_to_check & addr_mask);

As a consequence the cluster_base_addr_i has to be aligned to the the TCDM size, otherwise this check can't distinguish between routing to the TCDM or SoC/Periph. A static assertion checks that this holds true.