Subversion Repositories mips_enhanced

Prompt for target technology
CONFIG_SYN_INFERRED
  Selects the target technology for memory and pads. 
  The following are available:

  - Inferred: Generic FPGA or ASIC targets if your synthesis tool
    is capable of inferring RAMs and pads automatically.

  - Actel ProAsic/P/3 and Axellerator FPGAs
  - Aeroflex UT25CRH Rad-Hard 0.25 um CMOS 
  - Altera: Most Altera FPGA families
  - Altera-Stratix: Altera Stratix FPGA family
  - Altera-StratixII: Altera Stratix-II FPGA family
  - ATC18: Atmel-Nantes 0.18 um rad-hard CMOS
  - IHP25: IHP 0.25 um CMOS
  - IHP25RH: IHP Rad-Hard 0.25 um CMOS
  - Lattice : EC/ECP/XP FPGAs
  - Quicklogic : Eclipse/E/II FPGAs
  - UMC-0.18 : UMC 0.18 um CMOS with Virtual Silicon libraries
  - Xilinx-Spartan/2/3: Xilinx Spartan/2/3 libraries
  - Xilinx-Spartan3E: Xilinx Spartan3E libraries
  - Xilinx-Virtex/E: Xilinx Virtex/E libraries
  - Xilinx-Virtex2/4/5: Xilinx Virtex2/4/5 libraries


Ram library
CONFIG_MEM_VIRAGE
  Select RAM generators for ASIC targets. 

Infer ram
CONFIG_SYN_INFER_RAM
  Say Y here if you want the synthesis tool to infer your
  RAM automatically. Say N to directly instantiate technology-
  specific RAM cells for the selected target technology package.

Infer pads
CONFIG_SYN_INFER_PADS
  Say Y here if you want the synthesis tool to infer pads.
  Say N to directly instantiate technology-specific pads from
  the selected target technology package.

No async reset
CONFIG_SYN_NO_ASYNC
  Say Y here if you disable asynchronous reset in some of the IP cores.
  Might be necessary if the target library does not have cells with
  asynchronous set/reset.

Scan support
CONFIG_SYN_SCAN
  Say Y here to enable scan support in some cores. This will enable
  the scan support generics where available and add logic to make
  the design testable using full-scan.

Use Virtex CLKDLL for clock synchronisation
CONFIG_CLK_INFERRED
  Certain target technologies include clock generators to scale or
  phase-adjust the system and SDRAM clocks. This is currently supported
  for Xilinx, Altera and Proasic3 FPGAs. Depending on technology, you
  can select to use the Xilinx CKLDLL macro (Virtex, VirtexE, Spartan1/2),
  the Xilinx DCM (Virtex-2, Spartan3, Virtex-4), the Altera ALTDLL
  (Stratix, Cyclone), or the Proasic3 PLL. Choose the 'inferred' 
  option to skip a clock generator.

Clock multiplier
CONFIG_CLK_MUL
  When using the Xilinx DCM or Altera ALTPLL, the system clock can
  be multiplied with a factor of 2 - 32, and divided by a factor of
  1 - 32. This makes it possible to generate almost any desired 
  processor frequency. When using the Xilinx CLKDLL generator,
  the resulting frequency scale factor (mul/div) must be one of
  1/2, 1 or 2. On Proasic3, the factor can be 1 - 128.

  WARNING: The resulting clock must be within the limits specified
  by the target FPGA family.

Clock divider
CONFIG_CLK_DIV
  When using the Xilinx DCM or Altera ALTPLL, the system clock can
  be multiplied with a factor of 2 - 32, and divided by a factor of
  1 - 32. This makes it possible to generate almost any desired 
  processor frequency. When using the Xilinx CLKDLL generator,
  the resulting frequency scale factor (mul/div) must be one of
  1/2, 1 or 2. On Proasic3, the factor can be 1 - 128.

  WARNING: The resulting clock must be within the limits specified
  by the target FPGA family.

Output clock divider
CONFIG_OCLK_DIV
  When using the Proasic3 PLL, the system clock is generated by three
  parameters: input clock multiplication, input clock division and
  output clock division. Only certain values of these parameters
  are allowed, but unfortunately this is not documented by Actel.
  To find the correct values, run the Libero Smartgen tool and
  insert you desired input and output clock frequencies in the
  Static PLL configurator. The mul/div factors can then be read
  out from tool.

System clock multiplier
CONFIG_CLKDLL_1_2
  The Xilinx CLKDLL can scale the input clock with a factor of 0.5, 1.0, 
  or 2.0. Useful when the target board has an oscillator with a too high 
  (or low) frequency for your design. The divided clock will be used as the
  main clock for the whole processor (except PCI and ethernet clocks).

System clock multiplier
CONFIG_DCM_2_3
  The Xilinx DCM and Altera ALTDLL can scale the input clock with a large
  range of factors. Useful when the target board has an oscillator with a 
  too high (or low) frequency for your design. The divided clock will
  be used as the main clock for the whole processor (except PCI and 
  ethernet clocks). NOTE: the resulting frequency must be at least
  24 MHz or the DCM and ALTDLL might not work.

Enable CLKDLL for PCI clock
CONFIG_PCI_CLKDLL
  Say Y here to re-synchronize the PCI clock using a 
  Virtex BUFGDLL macro. Will improve PCI clock-to-output 
  delays on the expense of input-setup requirements.

Use PCI clock system clock
CONFIG_PCI_SYSCLK
  Say Y here to the PCI clock to generate the system clock.
  The PCI clock can be scaled using the DCM or CLKDLL to 
  generate a suitable processor clock.

External SDRAM clock feedback
CONFIG_CLK_NOFB
  Say Y here to disable the external clock feedback to synchronize the
  SDRAM clock. This option is necessary if your board or design does not
  have an external clock feedback that is connected to the pllref input
  of the clock generator.

Number of processors
CONFIG_PROC_NUM
  The number of processor cores. The LEON3MP design can accomodate
  up to 4 LEON3 processor cores. Use 1 unless you know what you are
  doing ...

Number of SPARC register windows
CONFIG_IU_NWINDOWS
  The SPARC architecture (and LEON) allows 2 - 32 register windows.
  However, any number except 8 will require that you modify and 
  recompile your run-time system or kernel. Unless you know what
  you are doing, use 8.

SPARC V8 multiply and divide instruction
CONFIG_IU_V8MULDIV
  If you say Y here, the SPARC V8 multiply and divide instructions
  will be implemented. The instructions are: UMUL, UMULCC, SMUL,
  SMULCC, UDIV, UDIVCC, SDIV, SDIVCC. In code containing frequent
  integer multiplications and divisions, significant performance
  increase can be achieved. Emulated floating-point operations will
  also benefit from this option.

  By default, the gcc compiler does not emit multiply or divide
  instructions and your code must be compiled with -mv8 to see any
  performance increase. On the other hand, code compiled with -mv8
  will generate an illegal instruction trap when executed on processors
  with this option disabled.

  The divider consumes approximately 2 kgates, the multiplier 6 kgates.

Multiplier latency
CONFIG_IU_MUL_LATENCY_4
  The multiplier used for UMUL/SMUL instructions is implemented
  with a 16x16 multiplier which is iterated 4 times. This leads
  to a 4-cycle latency for multiply operations. To improve timing,
  a pipeline stage can be inserted into the 16x16 multiplier which
  will lead to a 5-cycle latency for the multiply oprations.

Multiplier latency
CONFIG_IU_MUL_MAC
  If you say Y here, the SPARC V8e UMAC/SMAC (multiply-accumulate)
  instructions will be enabled. The instructions implement a
  single-cycle 16x16->32 bits multiply with a 40-bits accumulator.
  The details of these instructions can be found in the LEON manual,

Single vector trapping
CONFIG_IU_SVT
  Single-vector trapping is a SPARC V8e option to reduce code-size
  in small applications. If enabled, the processor will jump to 
  the address of trap 0 (tt = 0x00) for all traps. No trap table
  is then needed. The trap type is present in %psr.tt and must
  be decoded by the O/S. Saves 4 Kbyte of code, but increases
  trap and interrupt overhead. Currently, the only O/S supporting
  this option is eCos. To enable SVT, the O/S must also set bit 13
  in %asr17.

Load latency
CONFIG_IU_LDELAY
  Defines the pipeline load delay (= pipeline cycles before the data
  from a load instruction is available for the next instruction).
  One cycle gives best performance, but might create a critical path
  on targets with slow (data) cache memories. A 2-cycle delay can
  improve timing but will reduce performance with about 5%.

Reset address
CONFIG_IU_RSTADDR
  By default, a SPARC processor starts execution at address 0.
  With this option, any 4-kbyte aligned reset start address can be
  choosen. Keep at 0 unless you really know what you are doing.

Power-down
CONFIG_PWD
  Say Y here to enable the power-down feature of the processor.
  Might reduce the maximum frequency slightly on FPGA targets.
  For details on the power-down operation, see the LEON3 manual.

Hardware watchpoints
CONFIG_IU_WATCHPOINTS
  The processor can have up to 4 hardware watchpoints, allowing to 
  create both data and instruction breakpoints at any memory location,
  also in PROM. Each watchpoint will use approximately 500 gates.
  Use 0 to disable the watchpoint function.

Floating-point enable
CONFIG_FPU_ENABLE
  Say Y here to enable the floating-point interface for the MEIKO
  or GRFPU. Note that no FPU's are provided with the GPL version
  of GRLIB. Both the Gaisler GRFPU and the Meiko FPU are commercial 
  cores and must be obtained separately. 

FPU selection
CONFIG_FPU_GRFPU
  Select between Gaisler Research's GRFPU and GRFPU-lite FPUs or the Sun 
  Meiko FPU core. All cores  are fully IEEE-754 compatible and support
  all SPARC FPU instructions.

GRFPU Multiplier
CONFIG_FPU_GRFPU_INFMUL
  On FPGA targets choose inferred multiplier. For ASIC implementations 
  choose between Synopsys Design Ware (DW) multiplier or Module 
  Generator (ModGen) multiplier. DW multiplier gives better results 
  (smaller area  and better timing) but requires DW license. ModGen 
  multiplier is part of GRLIB and does not require license. 

Shared GRFPU
CONFIG_FPU_GRFPU_SH
  If enabled multiple CPU cores will share one GRFPU.   

GRFPC Configuration
CONFIG_FPU_GRFPC0
  Configures the GRFPU-LITE controller. 

  In simple configuration controller executes FP instructions 
  in parallel with  integer instructions. FP operands are fetched 
  in the register file stage and the result is written in the write 
  stage. This option uses least area resources.

  Data forwarding configuration gives ~ 10 % higher FP performance than 
  the simple configuration by adding data forwarding between the pipeline
  stages. 

  Non-blocking controller allows FP load and store instructions to
  execute in parallel with FP instructions. The performance increase is 
  ~ 20 % for FP applications. This option uses most logic resources and 
  is suitable for ASIC implementations. 
  
Floating-point netlist
CONFIG_FPU_NETLIST
  Say Y here to use a VHDL netlist of the GRFPU-Lite. This is
  only available in certain versions of grlib.

Enable Instruction cache
CONFIG_ICACHE_ENABLE
  The instruction cache should always be enabled to allow
  maximum performance. Some low-end system might want to
  save area and disable the cache, but this will reduce
  the performance with a factor of 2 - 3.

Enable Data cache
CONFIG_DCACHE_ENABLE
  The data cache should always be enabled to allow
  maximum performance. Some low-end system might want to
  save area and disable the cache, but this will reduce
  the performance with a factor of 2 at least.

Instruction cache associativity
CONFIG_ICACHE_ASSO1
  The instruction cache can be implemented as a multi-set cache with
  1 - 4 sets. Higher associativity usually increases the cache hit
  rate and thereby the performance. The downside is higher power
  consumption and increased gate-count for tag comparators.

  Note that a 1-set cache is effectively a direct-mapped cache.

Instruction cache set size
CONFIG_ICACHE_SZ1
  The size of each set in the instuction cache (kbytes). Valid values
  are 1 - 64 in binary steps. Note that the full range is only supported
  by the generic and virtex2 targets. Most target packages are limited
  to 2 - 16 kbyte. Large set size gives higher performance but might
  affect the maximum frequency (on ASIC targets). The total instruction
  cache size is the number of set multiplied with the set size.

Instruction cache line size
CONFIG_ICACHE_LZ16
  The instruction cache line size. Can be set to either 16 or 32
  bytes per line. Instruction caches typically benefit from larger
  line sizes, but on small caches it migh be better with 16 bytes/line
  to limit eviction miss rate.

Instruction cache replacement algorithm
CONFIG_ICACHE_ALGORND
  Cache replacement algorithm for caches with 2 - 4 sets. The 'random'
  algorithm selects the set to evict randomly. The least-recently-used
  (LRR) algorithm evicts the set least recently replaced. The least-
  recently-used (LRU) algorithm evicts the set least recently accessed.
  The random algorithm uses a simple 1- or 2-bit counter to select
  the eviction set and has low area overhead. The LRR scheme uses one
  extra bit in the tag ram and has therefore also low area overhead.
  However, the LRR scheme can only be used with 2-set caches. The LRU
  scheme has typically the best performance but also highest area overhead.
  A 2-set LRU uses 1 flip-flop per line, a 3-set LRU uses 3 flip-flops
  per line, and a 4-set LRU uses 5 flip-flops per line to store the access
  history.

Instruction cache locking
CONFIG_ICACHE_LOCK
  Say Y here to enable cache locking in the instruction cache.
  Locking can be done on cache-line level, but will increase the
  width of the tag ram with one bit. If you don't know what
  locking is good for, it is safe to say N.

Data cache associativity
CONFIG_DCACHE_ASSO1
  The data cache can be implemented as a multi-set cache with
  1 - 4 sets. Higher associativity usually increases the cache hit
  rate and thereby the performance. The downside is higher power
  consumption and increased gate-count for tag comparators.

  Note that a 1-set cache is effectively a direct-mapped cache.

Data cache set size
CONFIG_DCACHE_SZ1
  The size of each set in the data cache (kbytes). Valid values are
  1 - 64 in binary steps. Note that the full range is only supported
  by the generic and virtex2 targets. Most target packages are limited
  to 2 - 16 kbyte. A large cache gives higher performance but the
  data cache is timing critical an a too large setting might affect
  the maximum frequency (on ASIC targets). The total data cache size
  is the number of set multiplied with the set size.

Data cache line size
CONFIG_DCACHE_LZ16
  The data cache line size. Can be set to either 16 or 32 bytes per
  line. A smaller line size gives better associativity and higher
  cache hit rate, but requires a larger tag memory.

Data cache replacement algorithm
CONFIG_DCACHE_ALGORND
  See the explanation for instruction cache replacement algorithm.

Data cache locking
CONFIG_DCACHE_LOCK
  Say Y here to enable cache locking in the data cache.
  Locking can be done on cache-line level, but will increase the
  width of the tag ram with one bit. If you don't know what
  locking is good for, it is safe to say N.

Data cache snooping
CONFIG_DCACHE_SNOOP
  Say Y here to enable data cache snooping on the AHB bus. Is only
  useful if you have additional AHB masters such as the DSU or a
  target PCI interface. Note that the target technology must support
  dual-port RAMs for this option to be enabled. Dual-port RAMS are
  currently supported on Virtex/2, Virage and Actel targets.

Data cache snooping implementation
CONFIG_DCACHE_SNOOP_FAST
  The default snooping implementation is 'slow', which works if you 
  don't have AHB slaves in cacheable areas capable of zero-waitstates 
  non-sequential write accesses. Otherwise use 'fast' and suffer a 
  few kgates extra area. This option is currently only needed in
  multi-master systems with the SSRAM or DDR memory controllers.

Separate snoop tags
CONFIG_DCACHE_SNOOP_SEPTAG
  Enable a separate memory to store the data tags used for snooping.
  This is necessary when snooping support is wanted in systems 
  with MMU, typically for SMP systems. In this case, the snoop
  tags will contain the physical tag address while the normal
  tags contain the virtual tag address. This option can also be
  together with the 'fast snooping' option to enable snooping
  support on technologies without dual-port RAMs. In such case,
  the snoop tag RAM will be implemented using a two-port RAM.
  
Fixed cacheability map
CONFIG_CACHE_FIXED
  If this variable is 0, the cacheable memory regions are defined
  by the AHB plug&play information (default). To overriden the
  plug&play settings, this variable can be set to indicate which
  areas should be cached. The value is treated as a 16-bit hex value
  with each bit defining if a 256 Mbyte segment should be cached or not.
  The right-most (LSB) bit defines the cacheability of AHB address
  0 - 256 MByte, while the left-most bit (MSB) defines AHB address
  3840 - 4096 MByte. If the bit is set, the corresponding area is
  cacheable. A value of 00F3 defines address 0 - 0x20000000 and
  0x40000000 - 0x80000000 as cacheable.

Local data ram
CONFIG_DCACHE_LRAM
  Say Y here to add a local ram to the data cache controller.
  Accesses to the ram (load/store) will be performed at 0 waitstates
  and store data will never be written back to the AHB bus.

Size of local data ram
CONFIG_DCACHE_LRAM_SZ1
  Defines the size of the local data ram in Kbytes. Note that most
  technology libraries do not support larger rams than 16 Kbyte.

Start address of local data ram
CONFIG_DCACHE_LRSTART
  Defines the 8 MSB bits of start address of the local data ram.
  By default set to 8f (start address = 0x8f000000), but any value
  (except 0) is possible. Note that the local data ram 'shadows'
  a 16 Mbyte block of the address space.

MMU enable
CONFIG_MMU_ENABLE
  Say Y here to enable the Memory Management Unit.

MMU split icache/dcache table lookaside buffer
CONFIG_MMU_COMBINED
  Select "combined" for a combined icache/dcache table lookaside buffer,
  "split" for a split icache/dcache table lookaside buffer

MMU tlb replacement scheme
CONFIG_MMU_REPARRAY
  Select "LRU" to use the "least recently used" algorithm for TLB
  replacement, or "Increment" for a simple incremental replacement
  scheme.

Combined i/dcache tlb
CONFIG_MMU_I2
  Select the number of entries for the instruction TLB, or the
  combined icache/dcache TLB if such is used.

Split tlb, dcache
CONFIG_MMU_D2
  Select the number of entries for the dcache TLB.

Fast writebuffer 
CONFIG_MMU_FASTWB
  Only selectable if split tlb is enabled. In case fast writebuffer is
  enabled the tlb hit will be made concurrent to the cache hit. This 
  leads to higher store performance, but increased power and area.
  
DSU enable
CONFIG_DSU_ENABLE
  The debug support unit (DSU) allows non-intrusive debugging and tracing
  of both executed instructions and AHB transfers. If you want to enable
  the DSU, say Y here and select the configuration below.

Trace buffer enable
CONFIG_DSU_TRACEBUF
  Say Y to enable the trace buffer. The buffer is not necessary for
  debugging, only for tracing instructions and data transfers.

Enable instruction tracing
CONFIG_DSU_ITRACE
  If you say Y here, an instruction trace buffer will be implemented
  in each processor. The trace buffer will trace executed instructions
  and their results, and place them in a circular buffer. The buffer 
  can be read out by any AHB master, and in particular by the debug 
  communication link.

Size of trace buffer
CONFIG_DSU_ITRACESZ1
  Select the buffer size (in kbytes) for the instruction trace buffer. 
  Each line in the buffer needs 16 bytes. A 128-entry buffer will thus
  need 2 kbyte.

Enable AHB tracing
CONFIG_DSU_ATRACE
  If you say Y here, an AHB trace buffer will be implemented in the
  debug support unit processor. The AHB buffer will trace all transfers
  on the AHB bus and save them in a circular buffer. The trace buffer 
  can be read out by any AHB master, and in particular by the debug 
  communication link.

Size of trace buffer
CONFIG_DSU_ATRACESZ1
  Select the buffer size (in kbytes) for the AHB trace buffer. 
  Each line in the buffer needs 16 bytes. A 128-entry buffer will thus
  need 2 kbyte.


LEON3FT enable
CONFIG_LEON3FT_EN
  Say Y here to use the fault-tolerant LEON3FT core instead of the
  standard non-FT LEON3.

IU Register file protection 
CONFIG_IUFT_NONE
  Select the FT implementation in the LEON3FT integer unit 
  register file. The options include parity, parity with
  sparing, 7-bit BCH and TMR.

FPU Register file protection 
CONFIG_FPUFT_EN
  Say Y to enable SEU protection of the FPU register file.
  The GRFPU will be protected using 8-bit parity without restart, while
  the GRFPU-Lite will be protected with 4-bit parity with restart. If 
  disabled the FPU register file will be implemented using flip-flops.

Cache memory error injection
CONFIG_RF_ERRINJ
  Say Y here to enable error injection in to the IU/FPU regfiles.
  Affects only simulation.

Cache memory protection 
CONFIG_CACHE_FT_EN
  Enable SEU error-correction in the cache memories. 

Cache memory error injection
CONFIG_CACHE_ERRINJ
  Say Y here to enable error injection in to the cache memories.
  Affects only simulation.

Leon3ft netlist
CONFIG_LEON3_NETLIST
  Say Y here to use a VHDL netlist of the LEON3FT. This is
  only available in certain versions of grlib.

IU assembly printing
CONFIG_IU_DISAS
  Enable printing of executed instructions to the console.

IU assembly printing in netlist
CONFIG_IU_DISAS_NET
  Enable printing of executed instructions to the console also
  when simulating a netlist. NOTE: with this option enabled, it
  will not be possible to pass place&route.

32-bit program counters
CONFIG_DEBUG_PC32
  Since the LSB 2 bits of the program counters always are zero, they are
  normally not implemented. If you say Y here, the program counters will
  be implemented with full 32 bits, making debugging of the VHDL model
  much easier. Turn of this option for synthesis or you will be wasting
  area.


CONFIG_AHB_DEFMST
  Sets the default AHB master (see AMBA 2.0 specification for definition).
  Should not be set to a value larger than the number of AHB masters - 1.
  For highest processor performance, leave it at 0.

Default AHB master
CONFIG_AHB_RROBIN
  Say Y here to enable round-robin arbitration of the AHB bus. A N will
  select fixed priority, with the master with the highest bus index having
  the highest priority.

Support AHB split-transactions
CONFIG_AHB_SPLIT
  Say Y here to enable AHB split-transaction support in the AHB arbiter.
  Unless you actually have an AHB slave that can generate AHB split
  responses, say N and save some gates.

Default AHB master
CONFIG_AHB_IOADDR
  Selects the MSB adddress (HADDR[31:20]) of the AHB IO area, as defined 
  in the plug&play extentions of the AMBA bus. Should be kept to FFF 
  unless you really know what you are doing.

APB bridge address          
CONFIG_APB_HADDR
  Selects the MSB adddress (HADDR[31:20]) of the APB bridge. Should be
  kept at 800 for software compatibility. 

AHB monitor                 
CONFIG_AHB_MON
  Say Y to enable the AHB bus monitor. The monitor will check for
  illegal AHB transactions during simulation. It has no impact on
  synthesis.

Report AHB errors
CONFIG_AHB_MONERR
  Print out detected AHB violations on console.

Report AHB warnings
CONFIG_AHB_MONWAR
  Print out detected AHB warnings on console.


JTAG Enable
CONFIG_DSU_JTAG
  Say Y to enable the JTAG debug link (JTAG-to-AHB). Debugging is done 
  with GRMON through the boards JTAG chain at speed of 300 kbits/s. 
  Supported JTAG cables are Xilinx Parallel Cable III and IV.  

Leon2 memory controller
CONFIG_MCTRL_LEON2
  Say Y here to enable the LEON2 memory controller. The controller
  can access PROM, I/O, SRAM and SDRAM. The bus width for PROM
  and SRAM is programmable to 8-, 16- or 32-bits.

8-bit memory support
CONFIG_MCTRL_8BIT
  If you say Y here, the PROM/SRAM memory controller will support
  8-bit mode, i.e. operate from 8-bit devices as if they were 32-bit.
  Say N to save a few hundred gates.

16-bit memory support
CONFIG_MCTRL_16BIT
  If you say Y here, the PROM/SRAM memory controller will support
  16-bit mode, i.e. operate from 16-bit devices as if they were 32-bit.
  Say N to save a few hundred gates.

Write strobe feedback
CONFIG_MCTRL_WFB
  If you say Y here, the PROM/SRAM write strobes (WRITEN, WEN) will
  be used to enable the data bus drivers during write cycles. This
  will guarantee that the data is still valid on the rising edge of
  the write strobe. If you say N, the write strobes and the data bus
  drivers will be clocked on the rising edge, potentially creating
  a hold time problem in external memory or I/O. However, in all
  practical cases, there is enough capacitance in the data bus lines
  to keep the value stable for a few (many?) nano-seconds after the
  buffers have been disabled, making it safe to say N and remove a 
  combinational path in the netlist that might be difficult to 
  analyze.

Write strobe feedback
CONFIG_MCTRL_5CS
  If you say Y here, the 5th (RAMSN[4]) SRAM chip select signal will
  be enabled. If you don't intend to use it, say N and save some gates.

SDRAM controller enable
CONFIG_MCTRL_SDRAM
  Say Y here to enabled the PC100/PC133 SDRAM controller. If you don't
  intend to use SDRAM, say N and save about 1 kgates.

SDRAM controller inverted clock
CONFIG_MCTRL_SDRAM_INVCLK
  If you say Y here, the SDRAM controller output signals will be delayed
  with 1/2 clock in respect to the SDRAM clock. This will allow the used
  of an SDRAM clock which in not strictly in phase with the internal 
  clock. This option will limit the SDRAM frequency to 40 - 50 MHz.

  On FPGA targets without SDRAM clock synchronizations through PLL/DLL, 
  say Y. On ASIC targets, say N and tell your foundry to balance the 
  SDRAM clock output.

SDRAM separate address buses
CONFIG_MCTRL_SDRAM_SEPBUS
  Say Y here if your SDRAM is connected through separate address
  and data buses (SA & SD). This is the case on the GR-CPCI-XC2V6000
  board, but not on the GR-PCI-XC2V3000 or Avnet XCV1500E boards.

64-bit data bus
CONFIG_MCTRL_SDRAM_BUS64
  Say Y here to enable 64-bit SDRAM data bus.

Page burst enable
CONFIG_MCTRL_PAGE
  Say Y here to enable SDRAM page burst operation. This will implement
  read operations using page bursts rather than 8-word bursts and save
  about 500 gates (100 LUTs). Note that not all SDRAM supports page 
  burst, so use this option with care.

Programmable page burst enable
CONFIG_MCTRL_PROGPAGE
  Say Y here to enable programmable SDRAM page burst operation. This
  will allow to dynamically enable/disable page burst by setting
  bit 17 in MCFG2.

On-chip rom
CONFIG_AHBROM_ENABLE
  Say Y here to add a block on on-chip rom to the AHB bus. The ram
  provides 0-waitstates read access,  burst support, and 8-, 16- 
  and 32-bit data size. The rom will be syntheised into block rams
  on Xilinx and Altera FPGA devices, and into gates on ASIC 
  technologies. GRLIB includes a utility to automatically create
  the rom VHDL model (ahbrom.vhd) from an ELF file. Refer to the GRLIB
  documentation for details.

On-chip rom address
CONFIG_AHBROM_START
  Set the start address of AHB ROM (HADDR[31:20]). The ROM will occupy
  a 1 Mbyte slot at the selected address. Default is 000, corresponding
  to AHB address 0x00000000. When address 0x0 is selected, the rom area
  of any other memory controller is set to 0x10000000 to avoid conflicts.

Enable pipeline register for on-chip rom
CONFIG_AHBROM_PIPE
  Say Y here to add a data pipeline register to the on-chip rom.
  This should be done when the rom is implemenented in (ASIC) gates,
  or in logic cells on FPGAs. Do not use this option when the rom is
  implemented in block rams. If enabled, the rom will operate with 
  one waitstate.

On-chip ram
CONFIG_AHBRAM_ENABLE
  Say Y here to add a block on on-chip ram to the AHB bus. The ram
  provides 0-waitstates read access and 0/1 waitstates write access.
  All AHB burst types are supported, as well as 8-, 16- and 32-bit
  data size.

On-chip ram size
CONFIG_AHBRAM_SZ1
  Set the size of the on-chip AHB ram. The ram is infered/instantiated
  as four byte-wide ram slices to allow byte and half-word write
  accesses. It is therefore essential that the target package can
  infer byte-wide rams. This is currently supported on the generic,
  virtex, virtex2, proasic and axellerator targets.

On-chip ram address
CONFIG_AHBRAM_START
  Set the start address of AHB RAM (HADDR[31:20]). The RAM will occupy
  a 1 Mbyte slot at the selected address. Default is A00, corresponding
  to AHB address 0xA0000000.

UART1 enable
CONFIG_UART1_ENABLE
  Say Y here to enable UART1, or the console UART. This is needed to
  get any print-out from LEON3 systems regardless of operating system.

UART1 FIFO
CONFIG_UA1_FIFO1
  The UART has configurable transmitt and receive FIFO's, which can
  be set to 1 - 32 bytes. Use 1 for minimum area, or 8 - 32 for
  maximum throughput.


LEON3 interrupt controller
CONFIG_IRQ3_ENABLE
  Say Y here to enable the LEON3 interrupt controller. This is needed
  if you want to be able to receive interrupts. Operating systems like
  Linux, RTEMS and eCos needs this option to be enabled. If you intend
  to use the Bare-C run-time and not use interrupts, you could disable
  the interrupt controller and save about 500 gates.

LEON3 interrupt controller broadcast
CONFIG_IRQ3_BROADCAST_ENABLE
  If enabled the broadcast register is used to determine which
  interrupt should be sent to all cpus instead of just the first
  one that consumes it.
Timer module enable
CONFIG_GPT_ENABLE
  Say Y here to enable the Modular Timer Unit. The timer unit consists
  of one common scaler and up to 7 independent timers. The timer unit
  is needed for Linux, RTEMS, eCos and the Bare-C run-times.

Timer module enable
CONFIG_GPT_NTIM
  Set the number of timers in the timer unit (1 - 7).

Scaler width
CONFIG_GPT_SW
  Set the width if the common pre-scaler (2 - 16 bits). The scaler
  is used to divide the system clock down to 1 MHz, so 8 bits should
  be sufficient for most implementations (allows clocks up to 256 MHz).

Timer width
CONFIG_GPT_TW
  Set the width if the timers (2 - 32 bits). 32 bits is recommended
  for the Bare-C run-time, lower values (e.g. 16 bits) can work with
  RTEMS and Linux.

Timer Interrupt
CONFIG_GPT_IRQ
  Set the interrupt number for the first timer. Remaining timers will
  have incrementing interrupts, unless the separate-interrupts option
  below is disabled.

Watchdog enable
CONFIG_GPT_WDOGEN
  Say Y here to enable the watchdog functionality in the timer unit.

Watchdog time-out value
CONFIG_GPT_WDOG
  This value will be loaded in the watchdog timer at reset.

GPIO port
CONFIG_GRGPIO_ENABLE
  Say Y here to enable a general purpose I/O port. The port can be
  configured from 1 - 32 bits, whith each port signal individually
  programmable as input or output. The port signals can also serve
  as interrupt inputs.

GPIO port witdth
CONFIG_GRGPIO_WIDTH
  Number of bits in the I/O port. Must be in the range of 1 - 32.

GPIO interrupt mask
CONFIG_GRGPIO_IMASK
  The I/O port interrupt mask defines which bits in the I/O port
  should be able to create an interrupt. 

Text-mode VGA
CONFIG_VGA_ENABLE
  Say Y here to enable a simple text-mode VGA controller. The controller
  generate 48x36 characters on a 640x480 pixel screen. The pixel clock
  is 25 MHz.

SVGA frame buffer
CONFIG_SVGA_ENABLE
  Say Y here to enable a graphical frame buffer. The frame buffer
  can be configured up to 1024x768 pixels and 8-, 16- or 32-bit 
  colour depth. 

PS2 KBD interface
CONFIG_KBD_ENABLE
  Say Y here to enable a PS/2 keyboard or mouse interface.

UART debugging
CONFIG_DEBUG_UART
  During simulation, the output from the UARTs is printed on the
  simulator console. Since the ratio between the system clock and
  UART baud-rate is quite high, simulating UART output will be very
  slow. If you say Y here, the UARTs will print a character as soon
  as it is stored in the transmitter data register. The transmitter
  ready flag will be permanently set, speeding up simulation. However,
  the output on the UART tx line will be garbled.  Has not impact on
  synthesis, but will cause the LEON test bench to fail.

FPU register tracing
CONFIG_DEBUG_FPURF
  If you say Y here, all writes to the floating-point unit register file
  will be printed on the simulator console.