Altera® AXI4 Bus Functional Model User Guides

ID 838773
Date 5/19/2025
Public
Document Table of Contents

2.5.1.2.11. Data Members in Axi4StreamBytesDataError Class

The Axi4StreamBytesDataError class includes the following data members:

Data Member: error_mask_value {type: protected byte_t}

This status bit provides a summary indication of whether the byte provided in an object of class Axi4StreamBytesDataError has a bit or format error. This bit is managed by the class and may be checked with the data_has_errors() method. data_has_errors() returns data_value_has_errors as its return value.

Data Member: data_error_value {type: protected byte_t}

The value of the byte read using the standard get method get_data() does not retrieve data_value, as in the prior classes. In this error class, the value fetched is data_error_value, which is the data_value EXOR’ed with the error_mask_value.

The data_error_value updates whenever the data_value or error_mask_value is modified.

Data Member: signal_data_as_position_byte {type: protected bit}

This control bit, when set, causes a formatting error. Instead of signaling the byte using TKEEP and TSTRB as a Data byte with {TKEEP, TSTRB} = 2’b11, it is signaled as a Position byte with {TKEEP, TSTRB} = 2’b10.

You can use this to test your application to make sure that data stream decoding is being done properly. You can also use this to test your application for fault tolerance and error recovery.

When this setting is asserted to a 1’b1, this ensures that the other error bits, signal_data_as_null_byte and signal_data_as_reserved_byte, are cleared. Only one formatting error is valid at a time.

Data Member: signal_data_as_null_byte {type: protected bit}

This control bit, when set, causes a formatting error. Instead of signaling the byte using TKEEP and TSTRB as a Data byte with {TKEEP, TSTRB} = 2’b11, it is signaled as a Null byte with {TKEEP, TSTRB} = 2’b00.

You can use this to test your application to make sure that data stream decoding is being done properly. You can also use this to test your application for fault tolerance and error recovery.

When this setting is asserted to a 1’b1, this ensures that the other error bits, signal_data_as_position_byte and signal_data_as_reserved_byte, are cleared. Only one formatting error is valid at a time.

Data Member: signal_data_as_reserved_byte {type: protected bit}

This control bit, when set, causes a formatting error. Instead of signaling the byte using TKEEP and TSTRB as a Data byte with {TKEEP, TSTRB} = 2’b11, it is signaled as a reserved byte with {TKEEP, TSTRB} = 2’b01.

You can use this to test your application to make sure that data stream decoding is being done properly. You can also use this to test your application for fault tolerance and error recovery.

When this setting is asserted to a 1’b1, this ensures that the other error bits, signal_data_as_position_byte and signal_data_as_null_byte, are cleared. Only one formatting error is valid at a time.