$3\mathrm{.}3$ DATAPATH DESIGN

For the successful operation of a $4-$bit Smart Climate Control system, the Datapath needs specific logic

components such as a $2-$to$-4$ Line decoder, four $1-$bit AND gates, six $4-$bit $2-$to$-1$ Multiplexers, five $4-$bit

registers, two $4-$bit $4-$to$-1$ Multiplexers, and a $4-$bit Control and Calculation Unit $($CCU$)$ illustrated in Figure $1.$

Figure $1$: SCCS FSM & Datapath

Every logic block in the Datapath needs to be individually designed and simulated before being integrated

into the top$-$level design. The connections between each logic block must be established in the top$-$level design,

SCCS$\_$DATAPATH, using a hierarchical design approach.

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You are required to develop parameterized Verilog code to define your Datapath. The CLK and other

control signals should come from the FSM$.$

The FSM control signals and Datapath operations:

$$ wrt$\_$addr signal provides an address to activate the required register as stated in Table $1.$

Table $1$: $2-$to$-4$ Decoder Operation.

wrt$\_$addr Registers

A B REG$\_3$ REG$\_2$ REG$\_1$ REG$\_0$

$000001$

$010010$

$100100$

$111000$

$$ Toggle$\_$TH is used to switch between temperature and humidity settings.

$$ The wrt$\_$en signal collaborates with wrt$\_$addr and Toggle$\_$TH to choose either a new value or retain

the previous value of Temperature$/$Humidity$.$

$$ Input$\_$sel is used to select either the Sensor value or the User$-$defined value. $($Please note that in our

$4-$bit datapath, these values range between $0$ and $15).$

$$ The load$\_$data signal selects either the output of the input selection mux or the CCU output result.

$$ The rd$\_$addr$1$ and rd$\_$addr$2$ signals specify the register addresses necessary for executing the CCU

operation between two registers using the provided ccu$\_$opcode. The CCU must be designed to perform

the operations outlined in Table $2.$ You can use the behavioural approach to design the CCU.

Table $2$: CCU Opcodes and Instructions.

alu$\_$opcode Opr $1$ Opr $2$ Op Instruction

$000----$ noop $----$

$001$ xx $--$ set R$[$xx$]=1$

$010$ xx $--$ increment R$[$xx$]=$ R$[$xx$]+1$

$011$ xx $--$ decrement R$[$xx$]=$ R$[$xx$]-1$

$100$ xx $--$ load R$[$xx$]=$ Data$\_$in

$101$ xx $--$ store Data$\_$out $=$ R$[$xx$]$

$110$ xx yy compare R$[$xx$]=$ C$($R$[$xx$],$R$[$yy$])$

$111$ xx yy copy R$[$xx$]=$ R$[$yy$]$

$***$ Please note that these signals must be used in Datapath testbench to test all possible conditions required to

perform operations for SCCS$.$

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$3\mathrm{.}4$ FSM DESIGN

The control unit for this Datapath will be managed by the SCCS$\_$FSM$,$ which comprises two main

subcomponents: FSM and FSM$\_$DECO.

The SCCS$\_$FSM will be equipped with seven external inputs: START, TOGGLE, $3$ LED Flags

$($indicating the Sensor and User value comparison result$),$ CLK$,$ RESET and one output DONE to indicate

that the operation is complete. The FSM takes these inputs and carries out all necessary control functions and

generates three outputs: opcode, operand$1,$ and operand$2.$

The FSM$\_$DECO will then utilize these three outputs for decoding, following the guidelines outlined in

Table $3.$ The FSM$\_$DECO's output will be key in steering the Smart Climate Control system via the Datapath,

as illustrated in Figure $2.$

Table $3$: FSM$\_$DECO Operations.

Op op$\_$code Opr$1$ Opr$2$ ALU Rd$\_$addr$1$ Rd$\_$addr$2$ wrt$\_$addr wrt$\_$en load$\_$data Input$\_$sel

noop $000----000------0--$

set $001$ xx $--001----$ xx $10-$

inc $010$ xx $--010$ xx $--$ xx $10-$

dec $011$ xx $--011$ xx $--$ xx $10-$

load $100$ xx $--100----$ xx $111$ or $0$

store $101$ xx $--101$ xx $----0--$

compare $110$ xx yy $110$ xx yy xx $10-$

copy $111$ xx yy $111$ yy $--$ Xx $10-$

Figure $2$: SCCS Hardware Algori