HyperBus Memory Controller (HyperBus)

The HyperBus controller drives one or more HyperRAM / HyperFlash devices over the 8-bit double-data-rate HyperBus interface. The memory array is exposed as an ordinary memory-mapped window (load/store), while a separate configuration register block controls the PHY, access latency, the device configuration-register port, and a fault controller. Two generic soft-PHYs are provided for FPGA and simulation: an oversampling PHY (HyperBusGenericPhy, phy.clockDivider clocks per edge) and a full-rate DDR PHY (HyperBusGenericDdrPhy) that moves two bytes per clock through SoftDdr with no divider. A technology-specific PHY can be substituted for silicon. The controller and its register map are identical across PHYs.

Features

• 8-bit DDR HyperBus master with a generic oversampling soft-PHY

• Memory-mapped data window plus a TL-UL configuration register port

• Burst coalescing - a contiguous multi-word burst is issued as a single linear HyperRAM burst (one command-address), streamed through a pipelined send/receive path

• Abort/retry - if the master under-runs the write stream or fails to drain the read responses, the burst is aborted and re-issued from the first uncommitted word, so every word is delivered exactly once and in order

• Partitioning - up to 8 devices, each a partition selected by address range with an independent read-permission flag

• Configurable HyperRAM access latency and RESET# pulse/halt timing

• Device configuration-register access port (e.g. CR0)

• Fault controller latching address, permission, timeout and unaligned faults into a single, maskable error output

Partitioning

Each entry of partitions describes one device: its size (bytes) and whether reads are permitted. Partitions are concatenated from address 0, so partition n occupies [sum(sizes[0..n-1]), sum(sizes[0..n])). The controller decodes the access address to the owning partition and asserts that device’s chip select; an access outside every partition raises an address fault, and a read of a non-readable partition raises a permission fault.

Configuration

Available bus architectures:

• TileLink (dataBus TL-UH burst memory port + cfgBus TL-UL register port)

• AXI4-Shared

• BMB

By default, the configuration bus is defined with 10 bit address and 32 bit data width.

Parameter

HyperBusCtrl.Parameter

Name	Type	Description	Default
hyperbus.partitions	List[(BigInt, Boolean)]	Per-device (size, readable) list. Up to 8 devices.
phy.clockDivider	Int	Soft-PHY oversampling divider (clocks per HyperBus edge = divider / 2).	8
frontend.storageDepth	Int	Depth of the front-end / retry buffer (max coalesced burst length in words).	12
init.latencyCycles	Int	Reset default for the HyperRAM access latency (3..7).	7

object Parameter {
  def default(partitions: List[(BigInt, Boolean)]) = Parameter(
    hyperbus = HyperBusParameter(partitions),
    phy      = PhyParameter(),
    frontend = FrontendParameter(),
    init     = InitParameter()
  )
}

Register Mapping

IP Identification:

The register map starts with an IP Identification block to provide all information about the underlying IP core to software drivers. This allows to provide backwards compatible drivers.

IP Identification Registers

Address	Bit	Field	Default	Permission	Description
0x000	31 - 24	API	0x0	Rx	API version of the implemented IP Identification.
	23 - 16	Length	0x8	Rx	Length of the IP Identification block in Bytes.
	15 - 0	ID	0x19	Rx	IP value of this IP core.
0x004	31 - 24	Major Version	0x1	Rx	Major number if this IP core. Version schema is major.minor.patch.
	23 - 16	Minor Version	0x0	Rx	Minor number if this IP core. Version schema is major.minor.patch.
	15 - 0	Patch Version	0x0	Rx	Patch number if this IP core. Version schema is major.minor.patch.

Configuration Registers

Address	Bit	Field	Default	Permission	Description
0x010		reset_trigger		xW	Write any value to pulse RESET# using the configured pulse/halt widths.
0x014		reset_pulse	15	RW	RESET# assertion width, in clock cycles.
0x018		reset_halt	15	RW	Post-reset halt width before the first transaction, in clock cycles.
0x020	2 - 0	latency	7	RW	HyperRAM read/write access latency in cycles (3..7). Must match the device.
0x030	31 - 16	reg_access (write)	0x0	RW	Config-register port. Write: bit 15 = 1 read / 0 write, bits 14-0 = register address, bits 31-16 = write data.
	15	reg_access read-bit		RW	Set for a read command, clear for a write command.
	14 - 0	reg_access address		RW	Device configuration-register address. Read returns bit 31 = response valid, bit 16 = device fault, bits 15-0 = read data.
0x034	31 - 16	cmd_availability		Rx	Free entries in the register command FIFO (bits 15-0 hold response occupancy).
0x040	3 - 0	error_pending	0x0	RW	Latched faults, write 1 to clear: bit 0 address, bit 1 permission, bit 2 timeout, bit 3 unaligned.
0x044	3 - 0	error_mask	0x0	RW	Set a bit to report the corresponding fault on the error output.