A Verilog Code to mimic the functionality of the 8255 Interfacing Integrated Circuit Contains 38 pins
- Input ->
- wrb (write bar)
- rdb (read bar)
- address [2:0 ]
- reset (to initialize it )
InOut Ports ->
- data [7:0]
- PortA [7:0]
- PortB [7:0]
- PortC [7:0]
It operates in three modes - Mode 0 - where the three ports operate as input or output buses Mode 1 - where PortA and PortB operate as strobed input or output , and PortC supports in controlling Mode 2 - where PortA operates as strobed inout, Port b as simple input or output( same as in Mode 0 ) and PortC supports the functionality.
Testing
Mode 0 -> Done
Reading and Writing CWR and STATUS Register -> Done
Mode 1 -> Done
Mode 2 -> Done
Ref:
- Verilog Coding for Logic Synthesis by Weng Fook Lee (Wiley Publication)
- http://www.asic-world.com/verilog/veritut.html
- https://www.fpga4student.com/
- Verilog HDL - A Guide to Digital System and Synthesis by Samir Palnitkar