Why does Nios® V/g processor experiences data corruption when it is enabled with TCM and ECC?
Description Due to a problem in the Quartus ® Prime Pro Edition Software version 26.1, data corruption might occur in Nios ® V/g processor designs with tightly coupled memory (TCM) and error correction code (ECC). Both features must be enabled to observe this problem. It is caused by an RTL bug in the processor, which renders failure when the processor executes sw (store word), followed by sh (store halfword) or sb (store byte) instructions. For example, # Initially, value of Y is 0x0001CCCC. li t0, 0x12345678 li t1, 0x200A sw t0, 0(Z) # Store 0x12345678 word into Z sh t1, 0(Y) # Store 0x200A into lower half of Y Result Final value of Y Description Expected 0x0001200A Upper-half of Y is preserved as 0x0001, while lower-half of Y is changed to 0x200A. Actual (Data Corruption) 0x1234200A Upper-half of Y is corrupted to 0x1234, while lower-half of Y is changed to 0x200A. The 0x1234 is from the previous Store Word (sw) instruction. Resolution To work around this problem in the Quartus ® Prime Pro Edition Software version 26.1, apply either one of the solutions below: Disable TCM. Disable ECC. This problem is scheduled to be fixed in a future release of the Quartus ® Prime Pro Edition Software.Why does Ashling* RiscFree* IDE for Altera FPGAs software version 25.4.1 turns compiler warnings into errors?
Description In the Ashling* RiscFree* IDE for Altera FPGAs software version 25.4.1 (31 st Oct 2025) and later, you might see compilation error related to the following errors: Implicit int types (-Werror=implicit-int) Implicit function declarations (-Werror=implicit-function-declaration) Typos in function prototypes (-Werror=declaration-missing-parameter-type) Incorrect uses of the return statement (-Werror=return-mismatch) Using pointers as integers and vice versa (-Werror=int-conversion) Type checking on pointer types (-Werror=incompatible-pointer-types) This is due to an update in GCC 14 – GNU: Certain warnings are now errors, which affects future GCC versions. For more information, Ashling* RiscFree* IDE for Altera FPGAs software version 25.3.1 (1 st August 2025) is using GCC 13.2. Ashling* RiscFree* IDE for Altera FPGAs software version 25.4.1 (31 st Oct 2025) is using GCC 15.2. Thus, Ashling* RiscFree* IDE for Altera FPGAs software version 25.4.1 (31 st Oct 2025) and future versions are affected. Note that Ashling* RiscFree* IDE for Altera FPGAs software version 25.4.1 (31 st Oct 2025) is paired with Quartus ® Prime Pro Edition software version 26.1. Resolution GNU recommends resolving all the new errors for better code quality. If necessary, you may refer to the workaround – GNU: Turning errors back into warnings. In Board Support Package Editor, add "-fpermissive" in hal.make.cflags_user_flags.Why does downloading ELF file into Nios® V/g processor fail when disabled branch prediction, while enabled instruction cache?
Description Due to a problem in the Quartus ® Prime Pro Edition Software version 25.3.1, downloading ELF file into Nios ® V/g processor might fail when both the conditions below are fulfilled. Branch prediction is disabled, and Instruction cache is enabled The niosv-download command returns the error message below. Unexpected vCont reply in non-stop mode: E30 ERROR: GDB failed. This is because there is an RTL bug in the instruction cache related to its reset state. Resolution To work around this problem in the Quartus ® Prime Pro Edition Software version 25.3.1, Either enable branch prediction, Or disable instruction cache This problem is scheduled to be fixed in a future release of the Quartus ® Prime Pro Edition Software version 26.1.Why does Ashling* RiscFree* IDE for Altera* FPGA software reports unresolved inclusion warnings, despite a successful build of Nios® V processor software project?
Description Due to a problem in multiple versions of Ashling* RiscFree* IDE for Altera® FPGA, the unresolved inclusion warning might occur for any Nios ® V processor software projects. Note that, the warning is harmless. The affected software project will still build successfully. This is caused by a bug in the Indexer of Ashling* RiscFree* IDE, which fails to search for the relevant project files. The affected Ashling* RiscFree* IDE for Altera FPGA are: Software version v25.1.1 (dated as 31 st Jan 2025) Software version v25.2.1 (dated as 9 th May 2025) Software version v25.3.1 (dated 1 st August 2025) Resolution This problem is currently scheduled to be resolved in future release of Ashling* RiscFree* IDE for Altera FPGA software version v26.1.0 (dated as 19 th Dec 2025). Meanwhile, you may safely ignore this warning, as it does not affect the functionality of your project. If needed, please refer to the related article for the recommended workaround. Related Article: Ahsling RiscFree IDE 25.1.1: Unresolved inclusion | Altera CommunityWhy does the Nios® V processor that applies fast JTAG UART driver stop (stuck in a loop) when the JTAG UART terminal is not active?
Description Due to a problem in the Board Support Package Editor of Quartus ® Prime software, the JTAG UART driver for fast implementation might get stuck in a loop for any Nios ® V processor designs, when JTAG UART terminal is not active. This problem has been present since: Quartus ® Prime Pro Edition software version 21.3 Quartus ® Prime Standard Edition software version 22.1 It is because the JTAG UART IP is initialized before the Nios ® V processor initialization in alt_sys_init.c. For example: void alt_sys_init( void ) { ALTERA_AVALON_JTAG_UART_INIT (JTAG_UART, jtag_uart); INTEL_NIOSV_M_INIT (NIOS, nios); } Resolution To work around this problem, update the alt_sys_init.c to initialize the Nios ® V processor first. void alt_sys_init( void ) { INTEL_NIOSV_M_INIT (NIOS, nios); ALTERA_AVALON_JTAG_UART_INIT (JTAG_UART, jtag_uart); } This problem is currently scheduled to be resolved in a future release of the Quartus ® Prime software. Additional Information Refer to Embedded Peripherals IP User Guide [titled as JTAG UART Core - Driver Options: Fast vs. Small Implementations] for more information about the JTAG UART driver for fast (non-blocking) and slow (blocking) implementation. Related Article NIOSV firmware stuck when juart-terminal is not open for the print messages.Why does Nios® V processor design fail to compile during Analysis & Synthesis when the QSYS file is added into the Quartus® Prime project instead of the QIP file?
Description In the Quartus ® Prime Standard Edition software version 25.1, any Nios ® V processor designs might fail to compile during Analysis & Synthesis when the QSYS file is added into the Quartus ® Prime project. Here are the possible error messages that you might receive: Error (10170): Verilog HDL syntax error at niosv_cpp_fsm.sv(1418) near text: "'"; expecting ":", or "?", or binary operator. Error (10355): SystemVerilog Enumeration Type Declaration error at riscv.pkg.sv(1163): encoded value for element "MXL32" has width 32, which does not match the width of the enumeration's base type (2) Error (10835): SystemVerilog error at riscv.pkg.sv(149): no support for unions Error (16950): Verilog HDL error at : decimal constant 00000000000000010000000000000000 is too large, using 1874919424 instead Error (16814): Verilog HDL error at ... : unknown literal value 00000000000000010000000000000000 for parameter ... ignored This is because the Quartus ® Prime Standard Edition software version 25.1 has been updated to adhere to the software requirements below. This requirement is not mandatory in prior versions of the Quartus ® Prime Standard Edition software. Resolution To work around this problem in the Quartus ® Prime Standard Edition Software version 25.1, Remove the QSYS file from the project using the Remove Files in Project function. Add the QIP file to the project using the Add Files in Project function. Related Articles ERROR building simple NIOS® V Compact project Nios® V Synthesis Fails with Quartus® Prime 25.1 LiteWhy does Ashling* RiscFree* IDE for Altera® FPGAs fail to debug a Nios® V processor C++ software project in Windows?
Description Due to a problem with the Ashling* RiscFree* IDE for Altera ® FPGAs software, debugging a Nios ® V processor software project may fail when it is written in the C++ language. This is because there is a bug in the processor toolchain from the Ashling* RiscFree* IDE for Altera ® FPGAs software. C projects are not affected by this issue. You might receive the following error messages. Error Messages How is RISC-V GDB executed? Error in services launch sequence: GDB prompt not read From Ashling* RiscFree* IDE for Altera software ../../../gdb/gdb/cp-name-parser.y:192: internal-error: fill_comp: Assertion ‘i’ failed. Executing riscv32-unknown-elf-gdb commands in the command-line interface The affected Ashling* RiscFree* IDE for Altera ® FPGAs software versions are: 24.3.1 (version dated 9 th Aug 2024) 24.4.0 (version dated 27 th Sep 2024) 25.1.1 (version dated 31 st Jan 2025) Note that: This problem only affects Windows environments. C projects are not affected by this problem. Resolution This problem is fixed beginning with the Ashling* RiscFree* IDE for Altera ® FPGAs software version 25.2.1 (version dated 9 th May 2025). You can download Ashling* RiscFree* IDE for Altera ® FPGAs software version 25.2.1 (version dated 9 th May 2025) separately from Quartus® Prime Pro Edition Installer for software version 25.1.1. Follow these steps: Go to the Quartus® Prime Pro Edition Installer for software version 25.1.1 download link. Select Windows as the Operating System. Download the Quartus® Prime Pro Edition Installer for software version 25.1.1. Launch the installation. Select the following files to install: Add-ons and Standalone Software > Ashling* RiscFree* IDE for Altera Add-ons and Standalone Software > Quartus ® Prime Pro Edition Programmer and Tools Note: Refrain from using the Quartus® Prime Pro Edition Installer for software version 25.3 to resolve this problem. The installer contains the older version of the Ashling* software (Software version 25.1.1).Why does Nios® V processor simulation fail when using the generated VHDL testbench from Platform Designer?
Description Due to a problem in the Quartus ® Prime Standard Edition software version 25.1, Nios ® V processor simulation may fail with the generated VHDL testbench system from Platform Designer for any processor design. This problem affects: All Altera ® FPGA device families in Quartus ® Prime Standard Edition software, and All Nios ® V processor variants (Nios ® V/g, Nios ® V/m, and Nios ® V/c processors). It is because the generation of the Nios ® V processor VHDL testbench system is not supported in Quartus ® Prime Standard Edition software version 25.1. Resolution To work around this problem in the Quartus ® Prime Standard Edition Software version 25.1, please select “Verilog” at the “Create testbench simulation model” input option. This problem is currently scheduled to be resolved in a future release of the Quartus ® Prime Standard Edition software. Related Articles 3.3.1. Preparing Hardware Design for Simulation
Why does the Nios® V processor force Configuration Scheme with Memory Initialization for MAX® 10 FPGA?
Description Due to a problem in the Quartus® Prime Standard Edition Software version 23.1 and 24.1, you may see an error below when using Dual Compressed Image as the Internal Configuration mode for Nios® V Processor Design on MAX® 10 FPGA, Error (16031): The current Internal Configuration mode does not support memory initialization or ROM. Select Internal Configuration mode with ERAM. Note: Assuming that memory initialization is disabled in every on-chip memory. Resolution To work around this problem, Download and install the patches below for the Quartus® Prime Standard Edition Software version 24.1. Quartus® Prime Stardand Edition Software v24.1 Patch 0.01std for Windows (.exe) Quartus® Prime Stardand Edition Software v24.1 Patch 0.01std for Linux (.run) Readme for Quartus® Prime Stardand Edition Software v24.1 Patch 0.01std (.txt) Download and install the patches below for the Quartus® Prime Standard Edition Software version 23.1. Quartus® Prime Stardand Edition Software v23.1 Patch 0.03std for Windows (.exe) Quartus® Prime Stardand Edition Software v23.1 Patch 0.03std for Linux (.run) Readme for Quartus® Prime Stardand Edition Software v23.1 Patch 0.03std (.txt) The problem has been fixed starting with Quartus® Prime Standard Edition software version 25.1,Why does the Nios® V processor fail to generate HDL with an add_fileset_file error message in Quartus® Prime Standard Edition from Windows* OS?
Description Due to a problem in the Quartus® Prime Standard Edition Software versions 22.1, 23.1, and 24.1, the Nios® V processor might fail to generate HDL with an error message about add_fileset_file. This issue is present only on Windows OS. Example error message: Error: add_fileset_file: No such file <Nios V processor SystemVerilog file> while executing “add_fileset_file $current_sim/<Nios V processor SystemVerilog file> SYSTEM_VERILOG PATH $current_sim/<Nios V processor SystemVerilog file> $attr” This is because the Nios® V processor hw.tcl is calling add_fileset_file on an unsupported simulator. These unsupported simulators are referring to simulators that are not supported in Windows* OS - Cadence Simulator and Synopsys VCS* and VCS MX. Resolution To work around this problem in the Quartus® Prime Standard Edition Software version 24.1, download and install the patches below. The problem has been fixed starting with Quartus® Prime Pro Edition software version 25.1.1 and Quartus® Prime Standard Edition software version 25.1. Additional Information For information on the simulators’ supported platforms, refer to the Quartus® Prime Standard Edition User Guide: Third-party Simulation - Supported Simulators.
