Copyright	(C) 2015-2016 University of Twente 2017 Myrtle Software Ltd Google Inc.
License	BSD2 (see the file LICENSE)
Maintainer	Christiaan Baaij <christiaan.baaij@gmail.com>
Safe Haskell	Unsafe
Language	Haskell2010
Extensions	MonoLocalBinds ScopedTypeVariables BangPatterns GADTs GADTSyntax DataKinds FlexibleContexts MagicHash TypeOperators ExplicitNamespaces ExplicitForAll TypeApplications

Clash.Prelude.BlockRam.File

Contents

BlockRAM synchronised to an arbitrary clock

Description

Initialising a BlockRAM with a data file

BlockRAM primitives that can be initialised with a data file. The BNF grammar for this data file is simple:

FILE = LINE+
LINE = BIT+
BIT  = '0'
     | '1'

Consecutive LINEs correspond to consecutive memory addresses starting at 0. For example, a data file memory.bin containing the 9-bit unsigned number 7 to 13 looks like:

We can instantiate a BlockRAM using the content of the above file like so:

f :: HiddenClock domain -> Signal domain (Unsigned 3) -> Signal domain (Unsigned 9)
f rd = unpack <$> exposeClock blockRamFile clk d7 "memory.bin" rd (signal Nothing)

In the example above, we basically treat the BlockRAM as an synchronous ROM. We can see that it works as expected:

>>> import qualified Data.List as L
>>> L.tail $ sampleN 4 $ f (fromList [3..5])
[10,11,12]

However, we can also interpret the same data as a tuple of a 6-bit unsigned number, and a 3-bit signed number:

g :: HiddenClock domain -> Signal domain (Unsigned 3) -> Signal domain (Unsigned 6,Signed 3)
g clk rd = unpack <$> exposeClock blockRamFile clk d7 "memory.bin" rd (signal Nothing)

And then we would see:

>>> import qualified Data.List as L
>>> L.tail $ sampleN 4 $ g (fromList [3..5])
[(1,2),(1,3)(1,-4)]

Synopsis

blockRamFile :: (KnownNat m, Enum addr, HiddenClock domain gated, HasCallStack) => SNat n -> FilePath -> Signal domain addr -> Signal domain (Maybe (addr, BitVector m)) -> Signal domain (BitVector m)
blockRamFilePow2 :: forall domain gated n m. (KnownNat m, KnownNat n, HiddenClock domain gated, HasCallStack) => FilePath -> Signal domain (Unsigned n) -> Signal domain (Maybe (Unsigned n, BitVector m)) -> Signal domain (BitVector m)

BlockRAM synchronised to an arbitrary clock

blockRamFile Source #

Arguments

:: (KnownNat m, Enum addr, HiddenClock domain gated, HasCallStack)
=> SNat n	Size of the blockRAM
-> FilePath	File describing the initial content of the blockRAM
-> Signal domain addr	Read address `r`
-> Signal domain (Maybe (addr, BitVector m))	(write address `w`, value to write)
-> Signal domain (BitVector m)	Value of the `blockRAM` at address `r` from the previous clock cycle

Create a blockRAM with space for n elements

NB: Read value is delayed by 1 cycle
NB: Initial output value is undefined

NB: This function might not work for specific combinations of code-generation backends and hardware targets. Please check the support table below:

               | VHDL     | Verilog  | SystemVerilog |
===============+==========+==========+===============+
Altera/Quartus | Broken   | Works    | Works         |
Xilinx/ISE     | Works    | Works    | Works         |
ASIC           | Untested | Untested | Untested      |
===============+==========+==========+===============+

Additional helpful information:

See Clash.Prelude.BlockRam for more information on how to use a Block RAM.
Use the adapter readNew' for obtaining write-before-read semantics like this: readNew' clk (blockRamFile' clk size file) rd wrM.
See Clash.Prelude.BlockRam.File for more information on how to instantiate a Block RAM with the contents of a data file.
See Clash.Sized.Fixed for ideas on how to create your own data files.

blockRamFilePow2 Source #

Arguments

:: (KnownNat m, KnownNat n, HiddenClock domain gated, HasCallStack)
=> FilePath	File describing the initial content of the blockRAM
-> Signal domain (Unsigned n)	Read address `r`
-> Signal domain (Maybe (Unsigned n, BitVector m))	(write address `w`, value to write)
-> Signal domain (BitVector m)	Value of the `blockRAM` at address `r` from the previous clock cycle

Create a blockRAM with space for 2^n elements

NB: Read value is delayed by 1 cycle
NB: Initial output value is undefined

NB: This function might not work for specific combinations of code-generation backends and hardware targets. Please check the support table below:

               | VHDL     | Verilog  | SystemVerilog |
===============+==========+==========+===============+
Altera/Quartus | Broken   | Works    | Works         |
Xilinx/ISE     | Works    | Works    | Works         |
ASIC           | Untested | Untested | Untested      |
===============+==========+==========+===============+

Additional helpful information:

See Clash.Prelude.BlockRam for more information on how to use a Block RAM.
Use the adapter readNew' for obtaining write-before-read semantics like this: readNew' clk (blockRamFilePow2' clk file) rd wrM.
See Clash.Prelude.BlockRam.File for more information on how to instantiate a Block RAM with the contents of a data file.
See Clash.Sized.Fixed for ideas on how to create your own data files.