Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public
Document Table of Contents

5.4.6.1.1. Bus Interface Unit

The bus interface unit integrates the following components:

  • HRS – Host Register Set, implementation of additional registers not defined by the SD Host Controller Specification (released by SD Association) and specific to Cadence implementation of the SD host controller.
  • SRS – Slot Register Set, implementation of registers defined by the SD Host Controller Standard Specification.
  • CRS – Common Register Set, implementation of registers in the Common Register Area defined by SD Host Controller Standard Specification.
  • CQRS – Command Queuing Register Set, implementation of registers defined in section B.4. CQE Registers of the eMMC Standard 5.1. The registers are in the CQ module but accessible as any other register.
  • DMA – Direct memory access unit responsible for the data transfer between the external memory and the controller buffers. It works in one of three modes: SDMA, ADMA2, and ADMA3. The DMA has a manager port for access to system memory.
  • ADDRDEC – Address Decoder for Slave interface transactions.
  • CTRL – Command execution control module.
  • DCTRL – Data transfer control module includes SDMA, ADMA2 and ADMA3 engines.
  • FIN – FIFO Input Multiplexer/Arbiter, facilitate access to the internal FIFO. Two components have access to the FIFO Buffer Register (SRS08) and DMA engine.
  • DMA_ARB – DMA Arbiter, unit shares access to DMA between DCTRL and CQ.
  • TUNE – UHS-I SDR104 Tune Control module, gathers result from 40 iterations to calculate the center of the data valid window.
  • CQ Engine – Command Queuing Engine, control module which processes commands requested through CQ registers.
    • TDQUE – Task Doorbell Queue, list of requested tasks which waits to be sent to the device.
    • CQEQUE – Execution Queue, list of tasks sent to device and not executed.