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Notes on w11 systems: w11a for and Nexys 4


The sys_w11a_n4 system is a w11a implementation for the Digilent Nexys 4 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 PSRAM via nx_cram_memctl_as
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


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 4 board was the main w11 development platforms until it failed in July 2019. Until July 2019 the sys_w11a_n4 design was often FPGA tested with ostest against all oskits. Since July 2019 this design is only simulation tested.

  • 2019-07-20: board failed, from now on the design only simulation tested
  • 2013-09-22: initial version