AN 978: Nios® V Processor Migration Guidelines

ID 773196
Date 11/25/2024
Public
Document Table of Contents

5.3.1.1. Signal and Interface Mapping

Table 20.  Primary Interface
Interface Nios® V Processor Nios® II Processor Description
Clock clock clock Similar clock input
Reset reset reset Similar hard reset
Debug reset
  • dbg_reset_out
  • ndm_reset_in
debug_reset_request Mainly used to issue debug reset from CLI or IDE. By default, this feature is enabled in Nios® II/f processor but disabled in Nios® V/g processor.
Interrupts platform_irq_rx irq Nios® II/f processor supports32 platform interrupts. Nios® V/g processor supports 16 platform interrupts.
Timer and Software Interrupt Module timer_sw_agent Only supported in Nios® V processor. By default, it is connected to the data manager.
Debug dm_agent debug_mem_slave Allow JTAG download and debug. For Nios® V/g processor, by default, it is connected to the data manager and instruction manager.
Data bus data_manager data_master
  • Nios® II/f uses Avalon® memory-mapped interface
  • Nios® V/g processor uses Arm* AMBA* AXI-4 by default.
Instruction bus instruction_manager instruction_manager
  • Nios® II/f uses Avalon® memory-mapped interface
  • Nios® V/g processor uses Arm* AMBA* AXI-4 by default.
Custom instruction

(Instantiate in the Nios V Processor IP Parameter Editor)

custom_instruction_master
  • Nios® II/f implements custom instruction as primary interface.
  • Nios® V/g implements custom instruction as optional interface.
Table 21.  Optional Interface
Interface Nios® V Processor Nios® II Processor Description
Debug request
  • debugreq
  • debugack
Nios® V/g processor does not support debug requests.
CPU reset request
  • cpu_resetreq_resetreq
  • cpu_resetreq_ack
  • cpu_resetrequest
  • cpu_resettaken
Same application
ECC event cpu_ecc_status ecc_event_bus Same application
Custom instruction ci_custom<opcode>_<funct7[6:4]>
  • Nios® II/f implements custom instruction as primary interface.
  • Nios® V/g implements custom instruction as optional interface.
Tightly coupled memory (TCM
  • instruction_tcs
  • data_tcs
tightly_coupled_master Refer to the section Tightly Coupled Memory for more information.