Clash.Explicit.ROM.File

Initialising a ROM with a data file

ROMs 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:

000000111
000001000
000001001
000001010
000001011
000001100
000001101

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

f
  :: Clock  domain gated
  -> Signal domain (Unsigned 3)
  -> Signal domain (Unsigned 9)
f clk rd = unpack <$> romFile clk d7 "memory.bin" rd

And see that it works as expected:

>>> import qualified Data.List as L
>>> L.tail $ sampleN 4 $ f systemClockGen (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
  :: Clock  domain Source
  -> Signal domain (Unsigned 3)
  -> Signal domain (Unsigned 6,Signed 3)
g clk rd = unpack <$> romFile clk d7 "memory.bin" rd

And then we would see:

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

Synchronous ROM synchronised to an arbitrary clock

romFile

Arguments

:: (KnownNat m, Enum addr)

=> Clock domain gated

Clock to synchronize to

-> SNat n

Size of the ROM

-> FilePath

File describing the content of the ROM

-> Signal domain addr

Read address rd

-> Signal domain (BitVector m)

The value of the ROM at address rd from the previous clock cycle

A ROM with a synchronous read port, 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.Explicit.ROM.File for more information on how to instantiate a ROM with the contents of a data file.
• See Clash.Sized.Fixed for ideas on how to create your own data files.

romFilePow2

Arguments

:: (KnownNat m, KnownNat n)

=> Clock domain gated

Clock to synchronize to

-> FilePath

File describing the content of the ROM

-> Signal domain (Unsigned n)

Read address rd

-> Signal domain (BitVector m)

The value of the ROM at address rd from the previous clock cycle

A ROM with a synchronous read port, 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.Explicit.ROM.File for more information on how to instantiate a ROM with the contents of a data file.
• See Clash.Sized.Fixed for ideas on how to create your own data files.

Internal

romFile#

Arguments

:: KnownNat m

=> Clock domain gated

Clock to synchronize to

-> SNat n

Size of the ROM

-> FilePath

File describing the content of the ROM

-> Signal domain Int

Read address rd

-> Signal domain (BitVector m)

The value of the ROM at address rd from the previous clock cycle

romFile primitive