Scenario: You are to design synchronous and asynchronous circuits that will allow the following requirements to be met.
- Packet number checking
A synchronous sequential machine is to have a single input line and a single output line. The circuit is to receive messages of 4-bit words coded in binary (least significant bit first). The purpose of the circuit is to detect whether the number coming in is a prime number (divisible by only itself and 1). Thus, the output is to become 1 whenever a 4-bit word does represent a valid prime number. At the end of each word the machine is to return to the reset starting state.
1) Draw a State Diagram (Mealy) and check for redundancies
2) Then assign binary State Identifiers.
3) Make a Next State Truth Table (NSTT)
4) Select a bistable type
5) Determine expressions for the bistable inputs
6) Determine expressions for the outputs
2. Monitoring System
A monitoring system sends a fixed duration positive going pulses to a device to ensure that it is operating correctly. The device will respond by lowering its normally high line as soon as it receives the pulse then raising the line again within the 1ms if working correctly. If the device line doesn’t respond correctly by not raising the line or raising it then lowering it within the pulse period an alarm must occur. No response is not an alarm condition.
1) Carry out a design for the asynchronous system that will realise the requirements up to the point where internal conditions are designated to the lines in the merged table.
2) Explain what the designer would have to do to ensure the system was hazard free and the output was as short as possible.