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Memories LRAM640

Speedster22i Macro Cell Library

AchronixSemiconductorProprietary PAGE 159

Simultaneous Memory Operations

Memory operations may be performed simultaneously from both sides of the memory,

howeverthereisa restrictionwithmemory collisions.Amemorycollision isdefined asthe

condition where both of the ports access the same memory address within the same clock

cycle (both ports connected to the same clock), or

 within a TBD ps window (if each port is

connectedtoadifferentclock).Thedefinitionofa memorycollision dependsonwhetheror

nottheReadPortOutputRegisterisenabled.

If the Read Port Output Register in not enabled (reg_dout = 1’b0), a memory collision is

defined by reading the same address the cycle after a write command has occurred.If the

Read Port Output Reigister is enabled (reg_dout = 1’b1), a memory collision is defined by

reading the same address

 two cycle after a write command has occurred.If a memory

collisionoccurs,thewritetothememoryisvalid,butthereaddatamaybeincorrect.

LRAM640 Memory Initialization

Bydefault,thecontentsoftheLRAM640memoryareundefined.Iftheuserwantstheinitial

contentstobedefined,hemayassignthemfromeitherafilepointedtobythemem_init_file

parameterorassignthemfromthevalueofthemem_initparameter.

Thememoryisorganizedaslittle‐endianwithbit0mappedtobitzeroofparametermem_init

andbit639mappedtobit639ofparametermem_init.

TheLRAM640 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 def ine d by spaces or

 line separation. Each number is written as an 8‐bit hexadecimal

number.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 initia lizing the memory array

starting with address zero, moving upward. Each line consists as the  number itself

representedasahexadecimalnumber.

1 2 ... 171 172 173 174 175 176 177 178 179 180 181 ... 223 224

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Achronix Speedster22i User Macro Guide Bedienungsanleitung Seite 176