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2.3
Two-process design method
The dataflow style of coding would result in difficulty for reading and understanding the code
because of numerous number of concurrent statements and processes. Low abstraction level
and longer simulation time are other difficulties associated with the dataflow method. Twoprocess coding method helps to overcome these difficulties. Meanwhile to overcome these
difficulties some simple measures like using record types in all signal declarations, twoprocesses per entity and high level sequential statements[5]. Figure 6 shows two-process
design methodology.
Figure 6 : Generic two-process circuit [5]
Only two processes combinational (asynchronous) and sequential (registers) are used. The
complete design can be coded sequential in the combinational process and sequential process
updates the state using registers.
Following advantages are achieved by two-process design methodology
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Structured and readable VHDL code
Efficient simulation and synthesis
Easy code analyses and maintenance
Higher abstraction level
Simplified debugging and analysis
For further details please refer to two- process design documentation[5].
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