Nios® V Processor Reference Manual

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ID 683632
Date 10/31/2022
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Document Table of Contents
Document Table of Contents x
1. Overview 2. Nios® V/m Processor 3. Nios V Processor Reference Manual Archives 4. Document Revision History for the Nios® V Processor Reference Manual
1. Overview x
1.1. Intel® Quartus® Prime Software Support
2. Nios® V/m Processor x
2.1. Processor Performance Benchmarks 2.2. Processor Pipeline 2.3. Processor Architecture 2.4. Programming Model 2.5. Core Implementation
2.3. Processor Architecture x
2.3.1. General-Purpose Register File 2.3.2. Arithmetic Logic Unit 2.3.3. Reset and Debug Signals 2.3.4. Control and Status Registers 2.3.5. Exception Controller 2.3.6. Interrupt Controller 2.3.7. Memory and I/O Organization 2.3.8. RISC-V based Debug Module
2.3.6. Interrupt Controller x
2.3.6.1. Timer and Software Interrupt Module
2.3.7. Memory and I/O Organization x
2.3.7.1. Instruction and Data Buses
2.3.7.1. Instruction and Data Buses x
2.3.7.1.1. Instruction Manager Port 2.3.7.1.2. Data Manager Port 2.3.7.1.3. Address Map
2.3.8. RISC-V based Debug Module x
2.3.8.1. Debug Mode 2.3.8.2. Halt from Debug Module 2.3.8.3. Trigger 2.3.8.4. Abstract Commands in Debug Mode 2.3.8.5. Hardware/Software Interface
2.4. Programming Model x
2.4.1. Privilege Levels 2.4.2. Control and Status Registers (CSR) Mapping
2.4.1. Privilege Levels x
2.4.1.1. Machine Mode (M-mode) 2.4.1.2. Debug Mode (D-mode)
2.4.2. Control and Status Registers (CSR) Mapping x
2.4.2.1. Control and Status Register Field
2.5. Core Implementation x
2.5.1. Instruction Set Reference
1. Overview
2. Nios® V/m Processor
3. Nios V Processor Reference Manual Archives
4. Document Revision History for the Nios® V Processor Reference Manual

2.3.3. Reset and Debug Signals

Interface Type Description
reset Reset A global hardware reset input signal that forces the Nios® V processor to reset immediately.
dbg_reset_out Reset

An optional reset output signal which appear after you enable both Enable Debug and Enable Reset from Debug Module parameters.

  • This reset output signal is triggered by the JTAG debugger or niosv-download -r command.
  • You can connect this reset output signal to the following input signals:
    • To the ndm_reset_in input to reset the core and the timer module.
    • To the reset input signal of other components as needed.
ndm_reset_in Reset

An optional reset input signal which appear after you enable both Enable Debug and Enable Reset from Debug Module parameters.

  • You can use this signal to trigger reset controller to reset the core and the timer module.
  • The reset controller synchronizes the reset (hard reset) and ndm_reset_in signals.
cpu_resetreq Conduit An optional local reset ports which appear after you enable Add Reset Request Interface parameter. The signal consists of an input resetreq signal and an output ack signal that trigger the Nios® V processor to reset without affecting other components in a Nios® V processor system.
  • You can request a reset to the Nios® V processor core by asserting the resetreq signal.
  • The resetreq signal must remain asserted until the processor asserts ack signal. Failure for the signal to remain asserted can cause the processor to be in a non-deterministic state.
  • Assertion of the resetreq signal in debug mode has no effect on the processor's state.
  • The Nios® V processor responds that the reset is successful by asserting the ack signal.
  • After the processor is successfully reset, the assertion of the ack signal can happen multiple times periodically until the de-assertion of the resetreq signal.
Figure 3.  Nios® V Processor Reset Network
Level Two Title