Nios® V Processor Software Developer Handbook

ID 743810
Date 10/31/2022
Public

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6.6.6. Intel FPGA Logging Functions

The Intel FPGA logging functions provide a separate channel for sending logging and debugging information to a character-mode device, supplementing stdout and stderr. The Intel FPGA logging information can be printed in response to several conditions. Intel FPGA logging can be enabled and disabled independently of any normal stdio output, making it a powerful debugging tool.

When Intel FPGA logging is enabled, your software can print extra messages to a specified port with HAL function calls. The logging port, specified in the BSP, can be a UART or a JTAG UART device. In its default configuration, Intel FPGA logging prints out boot messages, which trace each step of the boot process.

Note: Avoid setting the Intel FPGA logging device to the device used for stdout or stderr. If Intel FPGA logging output is sent to stdout or stderr, the logging output might appear interleaved with the stdout or stderr output

Several logging options are available, controlled by C preprocessor symbols. You can also choose to add custom logging messages.

Intel FPGA logging changes system behavior. The logging implementation is designed to be as simple as possible, loading characters directly to the transmit register. It can have a negative impact on software performance.

Intel FPGA logging functions are conditionally compiled. When logging is disabled, it has no impact on code footprint or performance.

Note: The Intel FPGA reduced device drivers do not support Intel FPGA logging.