ADM-XRC SDK 2.8.1 User Guide (Linux)
© Copyright 2001-2009 Alpha Data
type byte_enable_t is array(natural range <>) of std_logic;
byte_enable_t is a vector type used to hold byte enables for a local bus transfer.
Use this vector type to hold the byte enables for a local bus transfer in a call to one of the following functions:
Each element of the vector corresponds to one byte of data, and normally the length of the vector should be same as the length of the byte_vector_t it is associated with. A '1' results in the corresponding bit of the local bus signal LBE# being asserted low.
To avoid confusion and problems related to ascending vs. descending ranges, the range of any objects of type byte_enable_t should always be ascending; for example:
variable data : byte_enable_t(0 to 15); -- Ok variable data : byte_enable_t(9 downto 3); -- NOT OK