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Blackfin FPGA EZ-Extender NMI Signal (Pin W21) Control

Question asked by zahidcalgary on Jul 27, 2011
Latest reply on Aug 4, 2011 by Prashant



I would like to control Blackfin NMI routine using FPGA EZ-Extender board. I noticed FPGA Pin W21 assigned as a NMI and it is contected with Blackfin processor NMI signal using expansion interface. I also figured out that FPGA Pin W21 (NMI) must be "low" and all unused FPGA pin must be configured as "Float" to run FPGA and Blackfin program sucessfully.


My intension is to control/run EX_NMI_HANDLER using FPGA pinW21(NMI). My understanding is if the Blackfin processor NMI signal become high than NMI_Handler subroutine will be executed.


I tried to control FPGA pinW21 (NMI) by program but unfortunately FPGA never allow me to pinW21 become high (while all unused pin configured "float"). As a experiment, I disconnected FPGA extender board from Blackfin (BF533) board and tried to pinW21 become "high". But, it also doesn't work. I go through details FPGA extender manual about this pin configuration/connection. I noticed I/O pin (IO_L19N_3_W21) of FPGA chip (SC3S1000) is directly connected with blackfin processor thorugh expansion B (pin 17).


Is there any suggestion on how FPGA pinW21 can be controlled by FPGA program (VHDL/Verilog) or any hardware configuration is necessary?