Achronix Speedster22i User Macro Guide - Manual (Page 119)

Memories BRAM80K
Speedster22i Macro Cell Library Achronix Semiconductor Proprietary PAGE 102
When the BRAM80K memory is configured with port widths of 9, 18, or 36 bits wide, the
initial memory contents may be defined by initializing the 256 256‐bit parameters initd_000
through initd_255 and the 32 256‐bit parameters initp_00 through initp_31. Each nine‐bit byte
is configured by programming the bottom eight bits of the byte to consecutive bytes of the
initd_000 through initd_255 parameters and programming the ninth bit to consecutive bits of
the initp_00 through initp_32 parameters. The parity memory is also organized as little‐endian
with the first parity bit location mapped to bit 0 of initp_00 and the last parity bit mapped to
the bit 255 of initp_31.
When the BRAM80K memory is configured with port widths of 10, 20, or 40 bits wide, the
initial memory contents may be defined by initializing the 256 256‐bit parameters initd_000
through initd_255, the 32 256‐bit parameters initp_00 through initp_31, and the 32 256‐bit
parameters initpx_00 through initpx_31. Each ten‐bit byte is configured by programming the
bottom eight bits of the byte to consecutive bytes of the initd_000 through initd_255
parameters, programming the ninth bit to consecutive bits of the initp_00 through initp_31
parameters and programming the tenth bit to consecutive bits of the initpx_00 through
initpx_31 parameters. The extended parity memory is also organized as little‐endian with the
first parity bit (tenth bit) location mapped to bit 0 of initpx_00 and the last parity bit mapped
to the bit 255 of initpx_31.
The BRAM80K memory block may alternatively be initialized with a memory file by setting
the mem_init_file to point to the path of a memory initialization file. The file format in the
latter case is defined by hexadecimal entries separated by white space, where the white space
is defined by spaces or line separation. Each number is hexadecimal of width equal to the
maximum value amongst the parameters: porta_read_width, porta_write_width,
portb_read_width, portb_write_width. A number entry may contain underscore (_) characters
amongst the digits, for example, A234_4567_33. Commenting is allowed following a double‐
slash (//) through to the end of the line. C‐like commenting is also allowed where the
characters between the /* and */ are ignored.
The memory is initialized starting with the first
entry of the file initializing the memory array starting with address zero, moving upward.
If the mem_init_value is defined, the BRAM80K will be initialized with the values defined in
the file pointed to by the mem_init_file parameter according to the format defined above. If
the mem_init_file is left at the default value of “”, the initial contents will be defined by the
values of the initd_000 ‐ initd_255, initp_00 ‐ initp_31, and the initpx_00 ‐ initpx_31
parameters. If the memory initialization parameters and the mem_init_file parameters are not
defined, the contents of the BRAM80K will not be initialized and the contents will be
unknown until the memory locations are written.