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Notes on w11 systems: w11a for Nexys A7-100 and Nexys 4 DDR


The sys_w11a_n4d system is a w11a implementation for the Digilent Nexys A7-100 board with DDR2 SDRAM support via a Vivado MIG core. The design is also compatible with the Nexys 4 DDR board. For complete configuration, see sys_conf.vhd. The most important features are:

Property Value
CPU options FPP: no; Cache: 32 kB
Memory 3840 kB from DDR2 SDRAM via miglib_nexys4d
Devices DL11:2; DZ11, PC11, LP11, DEUNA, RK11, RL11, RHRP, TM11, IIST, KW11P, M9312: yes
Diagnostics rbmon: yes; ibmon: yes; dmpcnt: yes; dmhbpt: 2; dmcmon: yes
Rlink 12 Mbps via FT2232HQ based serial link

An alternative design that uses only BRAM is available as sys_w11a_br_n4d.


The board has 16 LEDs and allows a nice console light emulation. The memory size of 3840 kB allows starting all oskits.

For complete instructions on how to run operating system images, see w11a_os_guide. The default setup is:

  SWI = 00000000 00101000   (gives console light display on LEDs)
  ti_w11 -tuD,12M,break,cts  @<oskit-name>_boot.tcl

Status & History

The Nexys A7-100 board is one of the main w11 development platforms. The sys_w11a_n4d design is often FPGA tested with ostest against all oskits.

  • 2019-08-10: procured Nexys A7-100 board. BUGFIX in MIG configuration. Now fully FPGA tested and verified.
  • 2019-01-02: initial version, only simulation tested (no board available for FPGA testing)