added gosset.txt to doc/ directory

[slipway.git] / doc / gosset.txt

Summary

  This document describes the correlation between publicly documented
  logic, I/O, and routing resources within the Atmel AT40k/94k family
  of chips and bits in the bitstreams needed to program them.

  Our goal is to make this information available to the public without
  restriction on its use, for the purpose of creating automated tools
  which generate bitstreams.


Statement of Public Knowledge

  The Knowledge encapsulated in this document was derived by formal
  scientific experimentation, using only information generally
  available to the public.  Extreme care which has been taken to
  ensure that the process did not violate any copyright, trademark,
  trade secret, or patent statutes.  No licensing contracts or
  non-disclosure agreements were entered into by the parties involved
  in this endeavor, nor did they have access to any confidential
  information.

  This document is part of the Public Domain; its authors surrender
  claim to copyright on it.


Corrections

  If you find errors in this document, please correct them and add the
  date and a short description of the correction to the table below.
  This will assist in merging changes made in disjoint derivitaves.

    2005.08.12  [gosset]  Initial revision
    2006.03.12  [megacz]  Swapped {L1,L0}->W, FB->{L0,L1}, {H0->L0,H1->L1}
    2006.03.13  [megacz]  Fixed lowest bit of z=00000000; it should be "1"
    2006.03.13  [megacz]  Corrected meaning of z-octet bits 2-4 in IOBs
    2006.03.13  [megacz]  Added constant zeroes in IOB section
    2006.04.15  [megacz]  un-swapped FB->{L0,L1}
    2007.09.01  [megacz]  fix column clocking bits

Background

  The Atmel AT40k Datasheet describes in great detail the resources
  available in the AT40k as well as the FPGA portion of the AT94k
  (which is functionally identical and uses the same binary
  configuration format).

  The configuration space used to control these resources consists of
  a collection of independent octets arranged in a sparse 24-bit
  address space.  This document correlates those bits with the
  resources described in the Datasheet.

  The process of configuring the device consists of writing these
  octets into the configuration memory.  Once the desired
  configuration octets are known, the procedures for loading them into
  configuration memory are well documented in Atmel Documents 1009 and
  2313.

  Each data octet "D" has a 24-bit address, divided into three address
  octets "X", "Y", and "Z".  In general, the X and Y address octets
  are related to the physical position of the resource, while the Z
  octet is related to the type of resource being addressed.

Notation

  We will use the notation A->B to indicate that setting the
  corresponding configuration bit high causes source A to drive wire
  B, and the notation A<>B to indicate that a pass gate between A and
  B is enabled.  The notation ~A or ~A->B indicates a configuration
  bit controlling A or causing A to drive B is *active low*
  (inverted).

  We will use the following terms to describe routing resources.
  They vary slightly from Atmel's documentation, but are less
  ambiguous.

   X, Y, W, Z   The cell's inputs
   XO, YO       The X and Y outputs from the cell (to its neighbors)
   N, S, E, W   Orthogonal lines: connections to neighboring cells
   NE,SE,NW,SW  Diagonal lines: connections to neighboring cells
   S0..S4       Quad lines: four-cell long routing lines
     H0..H4       Horizontal quad lines
     V0..V4       Vertical quad lines
   L0..L4       Switchbox ports: the wires joining FB,H0..H4,V0..V4,X,Y,Z,W
   G0a..G4b     Global lines: eight-cell long routing lines, in two sets (a+b)
   FB           The cell's internal feedback line
   R            The cell's internal register
   C            The cell's "center" output; can drive the X or Y outputs
   ZM           The "Z-mux"; the mux which drives the cell's register input
   WM           The "W-mux"; the mux which drives the third input to the LUTs
   XL, YL       The output of the X,Y-LUTs
   IA           The "internal and" gate (W & Z)
   

Cartesian Resources

  Although the exact interpretation of the X and Y octets depends on
  the resource type (Z octet), in most cases the X and Y octets are
  the cartesian coordinates of the logic cell nearest to the desired
  resource (0,0 is the lower-left hand logic cell).  This section
  describes the significance of the Z and D octets for such resources.

  Notes:
    - The most significant four bits of the Z octet are 0000 for these bits
    - If WZ->WM and FB->WM are both low, then W->WM.
    - If ZM->R and YL->R are both low, then the XL->R
    - The ZM->C and ZM->FB bits are used to bypass the register (when high).
    - ~SET bit controls the set/reset behavior of the register; 0=set, 1=reset

  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |Z3:0|                           D  octet                                    |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0000| V4->L4 | H4->L4 | FB->L2 | FB->L3 | FB->L1 | FB->L0 | FB->L4 |   1    |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0001| ZM->R  | YL->R  | WZ->WM | FB->WM | ZM->C  | ZM->FB |  C->XO |  C->YO |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0010| L4->Z  | L4->Y  | L3->Z  | L2->Z  | L1->Z  | L0->Z  | V4->OE | H4->OE |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0011| L2->W  | L3->W  | L4->W  | L4->X  | L0->W  | L1->W  |H2a<>V2a|H3b<>V3b|
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0100|  N->Y  |  S->Y  |  W->Y  |  E->Y  | L0->Y  | L1->Y  | L2->Y  | L3->Y  |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0101| SW->X  | NE->X  | SE->X  | NW->X  | L0->X  | L1->X  | L2->X  | L3->X  |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0110|                  X-LUT truth table, inverted                          |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0111|                  Y-LUT truth table, inverted                          |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |1000| V3->L3 | H3->L3 | H2->L2 | V2->L2 | V1->L1 | H0->L0 | V0->L0 | H1->L1 |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |1001|H1a<>V1a|H0a<>V0a|H0b<>V0b|H4a<>V4a|H4b<>V4b|H1b<>V1b|H3a<>V3a|H2b<>V2b|
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  ...
  +----+--------+--------+--------+--------+--------+--------+--------+--------+
  |0001|   1    |   1    |   1    |   1    |  ~SET  |   1    |   1    |   1    |
  +----+--------+--------+--------+--------+--------+--------+--------+--------+


Sector Resources

  Clocking, reset, and inter-sector repeaters are resources which are
  not specific to a particular cell.  As such, their X,Y addressing is
  slightly different.  These resources are addressed by the cartesian
  coordinates of the cell above or to the right of the resource, with
  an additional twist: for resources in vertical channels, the
  X-coordinate is shifted right by two bits (divided by four); for
  resources in horizontal channels, the Y-coordinate is shifted right
  by two bits (divided by four).

  The most significant three bits of the Z-octet for a sector resource
  are set to 001; the next bit (fourth most significant) is set to 0
  for horizontal channels and 1 for vertical channels.

  One sector wire and one global wire enter each side of each
  repeater, for a total of four connections.  Each connection has an
  associated four-bit code which indicates if that connection is
  driven by the repeater, and if so, which connection to the repeater
  is used to drive it:

     000 - driver disabled
     100 - source is global wire on the other side of the repeater
     010 - source is sector wire on the other side of the repeater
     001 - source is other connection on the same side of the repeater
  
  Example: a code of 001 for the left-hand side sector wire driver
  means that the source of the driver should be the left hand side
  global wire.  A code of 010 for the top sector wire driver means that
  the source of the driver should be the bottom sector wire.

     CC     = column clock
     CR     = column reset
     SC     = sector clock
     SC+    = sector clock of the sector below this one
     InvSC  = invert the clock source (CC or S4) before driving SC

  Note that you must set both CC->SC in the desired sector and CC->SC+
  in the sector above the desired sector in order to receive a column
  clock.

  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | Z octet  |                    D  octet                           |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0000 |   1    |   0    | Left/Top      G4 | Left/Top      S4 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0001 |   0    | S4->CR | Right/Bottom  G4 | Right/Bottom  S4 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0010 |   1    |   0    | Left/Top      G3 | Left/Top      S3 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0011 |   1    |   1    | Right/Bottom  G3 | Right/Bottom  S3 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0100 |   1    |   0    | Left/Top      G2 | Left/Top      S2 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0101 | CC->SC+| S3->SC | Right/Bottom  G2 | Right/Bottom  S2 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0110 |   1    |   0    | Left/Top      G1 | Left/Top      S1 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_0111 |   1    |   1    | Right/Bottom  G1 | Right/Bottom  S1 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_1000 |   1    |   0    | Left/Top      G0 | Left/Top      S0 |
  +----------+--------+--------+-----+-----+------+-----+-----+------+
  | 001_1001 | InvSC  | CC->SC | Right/Bottom  G0 | Right/Bottom  S0 |
  +----------+--------+--------+----+--------+----+-----+--------+---+


Block Memories

  Although block memories are shown in the lower right hand corner of
  each sector in the Atmel Datasheets, they are conceptually addressed
  by the cartesian coordinate of the cell in the lower *left* hand
  corner of the sector.  Furthermore, both coordinates are shifted
  right two bits (divided by four).

  The significance of the "D" octet for a given block memory depends
  on its position; if it falls in an odd sector-column (4-7, 12-15,
  etc), use the first chart; otherwise, use the second chart.

    USECLK = the memory is synchronous
    ENABLE = the memory is enabled
      DUAL = enable both ports on a dual-ported memory

  Odd Sector-Columns

  +--------+------+------+------+------+--------+--------+--------+---------+
  |Z octet |                       D octet                                  |
  +--------+------+------+------+------+--------+---------+--------+--------+
  |01000000|  1   |  1   |  1   |  1   |   1    |    1    |   1    |   1    |
  +--------+------+------+------+------+--------+---------+--------+--------+
  |01000001|  1   |  1   |  1   |  1   | USECLK | ~ENABLE | ENABLE | ENABLE |
  +--------+------+------+------+------+--------+---------+--------+--------+

  Even Sector-Columns

  +--------+------+------+------+------+--------+--------+--------+--------+
  |Z octet |                       D octet                                 |
  +--------+------+------+------+------+--------+--------+--------+--------+
  |01000000|  1   |  1   |  1   |  1   | USECLK |  DUAL  | ~DUAL  | ENABLE |
  +--------+------+------+------+------+--------+--------+--------+--------+
  |01000001|  1   |  1   |  1   |  1   |   1    |   1    |   1    |   1    |
  +--------+------+------+------+------+--------+--------+--------+--------+


I/O Blocks

  The Z octet for I/O resources always its most significant three bits
  set to 011.  The next bit is 1 for North/South IO Blocks and 0 for
  East/West IO Blocks.  The next bit is always 0, and the bit
  following that is set to 0 for primary (orthogonally connected)
  IOBs, 1 for secondary (diagonally connected) IOBs.

      S  = Sector wires of this cell
      S+ = Sector wires of next cell
      S- = Sector wires of previous cell
      G  = Global wires of this cell
      G+ = Global wires of next cell
  Output = Allow output from this IOB
      OE = when low, output is always enabled
     OEM = 7 bits, one-hot encoded, chooses input to output-enable mux
  USEOEM = when low, ignore the output enable mux
   Delay = amount of delay to add; can be 0, 1, 3, or 5
    Slew = slew time: 11=fast, 10=med, 01=slow
    Pull = 00=pullup, 11=pulldown, 01=none

  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |Z octet |                         D  octet                                  |
  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |011_0_00| Schmit |      Slew     |~G2->CR|   0   |       Pull      |    0   |
  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |011_0_01|REG->OUT|    0   |  OE  |              Output Mux                  |
  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |011_0010|      Added Delay (primary)     |PRI->S-| PRI->G+| PRI->G | PRI->S |
  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |011_0110|      Added Delay (secondary)   |SND->S | SND->S+|PRI->REG|SND->REG|
  +--------+--------+--------+------+-------+-------+--------+--------+--------+
  |011_0_11|  OEM   | USEOEM |                   OEM                           |
  +--------+--------+--------+------+-------+-------+--------+--------+--------+


Global Clock/Reset Networks

  To drive a column clock from one of the eight global clock/reset
  networks, set the corresponding bit in the desired column:

  +--------+--------+--------+
  |Z octet |X octet |Y octet |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+
  |01010000| column |00000000| CK8 | CK7 | CK6 | CK5 | CK4 | CK3 | CK2 | CK1 |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+

Unknown

  The following configuration resources are not fully understood, but
  the values below appear to work.

  +--------+--------+--------+
  |Z octet |X octet |Y octet |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+
  |        |00000000|00000000|  1  |  1  |  1  |  1  |  1  |  1  | GCK  SRC  |
  |10100001|00010111|00000000|  1  |  1  |  1  |  1  |  1  |  1  | GCK  SRC  |
  |        |00101111|00000000|  1  |  1  |  1  |  1  |  1  |  1  | GCK  SRC  |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+
  |11010000|00000000|00000000|  1  |  1  |  0  |  0  |  0  |  0  |  0  |  0  |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+
  |11010011|00000000|00000000|  0  |  0  |  0  |  0  |  1  |  1  |  0  |  1  |
  +--------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+