The SP486 and SP487 are low–power quad differential line drivers meeting RS-485 and RS-422
standards. The SP486 features a common driver enable control the SP487 provides independent
driver enable controls for each pair of drivers. Both feature tri–state outputs and wide
common–mode input range. Both are available in 16–pin plastic DIP and SOIC packages.
本文論述了狀態機的verilog編碼風格,以及不同編碼風格的優缺點，Steve Golson's 1994 paper, "State Machine Design Techniques for Verilog and VHDL" [1], is agreat paper on state machine design using Verilog, VHDL and Synopsys tools. Steve's paper alsooffers in-depth background concerning the origin of specific state machine types.This paper, "State Machine Coding Styles for Synthesis," details additional insights into statemachine design including coding style approaches and a few additional tricks.
One of the strengths of Synplify is the Finite State Machine compiler. This is a powerfulfeature that not only has the ability to automatically detect state machines in the sourcecode, and implement them with either sequential, gray, or one-hot encoding. But alsoperform a reachability analysis to determine all the states that could possibly bereached, and optimize away all states and transition logic that can not be reached.Thus, producing a highly optimal final implementation of the state machine.
Finite state machines are widely used in digital circuit designs. Generally, when designing a state machine using an HDL, the synthesis tools will optimize away all states that cannot be reached and generate a highly optimized circuit. Sometimes, however, the optimization is not acceptable. For example, if the circuit powers up in an invalid state, or the circuit is in an extreme working environment and a glitch sends it into an undesired state, the circuit may never get back to its normal operating condition.
本文論述了狀態機的verilog編碼風格,以及不同編碼風格的優缺點，Steve Golson's 1994 paper, "State Machine Design Techniques for Verilog and VHDL" [1], is agreat paper on state machine design using Verilog, VHDL and Synopsys tools. Steve's paper alsooffers in-depth background concerning the origin of specific state machine types.This paper, "State Machine Coding Styles for Synthesis," details additional insights into statemachine design including coding style approaches and a few additional tricks.
One of the strengths of Synplify is the Finite State Machine compiler. This is a powerfulfeature that not only has the ability to automatically detect state machines in the sourcecode, and implement them with either sequential, gray, or one-hot encoding. But alsoperform a reachability analysis to determine all the states that could possibly bereached, and optimize away all states and transition logic that can not be reached.Thus, producing a highly optimal final implementation of the state machine.
Finite state machines are widely used in digital circuit designs. Generally, when designing a state machine using an HDL, the synthesis tools will optimize away all states that cannot be reached and generate a highly optimized circuit. Sometimes, however, the optimization is not acceptable. For example, if the circuit powers up in an invalid state, or the circuit is in an extreme working environment and a glitch sends it into an undesired state, the circuit may never get back to its normal operating condition.
