FINITE STATE MACHINE with DATAPATH

FINITE STATE MACHINE with DATAPATH SYNTHESIS Dr Le Dung Hanoi University of Science and Technology FSMD MODEL Data inputs Status signals Controller inputs Controller Datapath Control signals Data outputs Controller outputs Datapath  performs the computations on data Controller  indicates to the datapath which operations have to be carried out on which data (algorithm) Dr Le Dung Hanoi University of Science and Technology Datapath Design Temporary storage:  registers, (shift registers), counters, register files, FIFOs, LIFOs Functional units:  arithmetic units, logical units and (barrel shifter) Connections:  data busses, multiplexers, tri-state buffers Shift register (temporary store)  Register (temporary store) Barrel shifter (functional unit) Dr Le Dung Hanoi University of Science and Technology Temporary storage Inputs Reset Load R L Register C Inputs Reset Up/Down Load Clock Output RE RA(n) Write Enable Write Address (n bits) WE WA(n) Register Files 2n Clock Output Inputs Read Enable Read Address (n bits) R U/D Counter C L C Clock Output Dr Le Dung Hanoi University of Science and Technology Register Files Dr Le Dung Hanoi University of Science and Technology Functional Units • Arithmetic units : Adder, Subtractor, Multiplier, Divider • Logical units : Comparator, AND, OR, XOR … • Barrel shifter : a digital circuit that can shift a data word by a specified number of bits in one clock cycle Dr Le Dung Hanoi University of Science and Technology Eight-bit Barrel Shifter bits input Shift Number (0-7) Sh 8-bit Barrel shifter Nr bits output Dr Le Dung Hanoi University of Science and Technology Generic structure of the Datapath External inputs Connections Temporary storage Connections Operand switching network Functional units Connections Result switching network External outputs Dr Le Dung Hanoi University of Science and Technology Connections in Datapath Inputs k0 k1 S MUX R L RE RA(n) Register Files 2n Register C ROE WE WA(n) R U/D Counter C L C COE Tri-buffer Data busses Data busses Comparator < = > F AOE Dr Le Dung ALU Tri-buffer Barrel shifter BOE Sh Nr Outputs OOE Hanoi University of Science and Technology Example 1: Datapath design (1) • Each variable and constant corresponds to a register or counter • Each operator corresponds to a functional unit Algorithm : Temporary storage: input sum; FOR i = TO sum i x input x; sum = sum + x; ENDFOR outport sum; Dr Le Dung  Register  Up counter  Register  Register Functional units: + >5  Adder  Comparator Hanoi University of Science and Technology Example 1: Datapath design (2) • Connect outputs of registers and counter to input of functional units • Connect output of functional units to input of registers and counter input sum; FOR i = TO input x; sum = sum + x; ENDFOR outport sum; Input L C 1 Register =5 k1 k0 Up Counter i C U L Comparator < L Register x C S L MUX Register sum C Output Adder (status) Dr Le Dung Hanoi University of Science and Technology Example 1: Controller design State A =  k0 Input sum; FOR i = TO input x; sum = sum + x; ENDFOR outport sum; Start=1 Controller C Clk Dr Le Dung One-hot FSM State B =0 Start Start=0  D-FF design State C =1 State D =1 C State F =1 State E =1 Hanoi University of Science and Technology Example 2: FSMD Design Dr Le Dung Hanoi University of Science and Technology Exercise Thiết kế Datapath cho FSMD thực thuật toán đếm tính tổng số lớn 10 số x đựơc đưa vào sau: cnt=0; sum=0; Repeat input x if (x> 10) then cnt=cnt + 1; sum=sum + x; end if; until x =0; output sum; output cnt; Chú ý: ≤ x ≤255, 0≤ sum ≤255 Các lệnh viết hàng thực song song Chỉ rõ ghi datapath bit Dr Le Dung Hanoi University of Science and Technology [...]... design State A 1 = 0  k0 Input sum; FOR i = 1 TO 5 input x; sum = sum + x; ENDFOR outport sum; Start=1 Controller C 2 3 4 5 6 Clk Dr Le Dung One-hot FSM State B 1 =0 2 3 1 Start Start=0  D-FF design State C 1 =1 4 State D 1 =1 2 0 C 1 State F 1 =1 6 State E 1 =1 5 Hanoi University of Science and Technology Example 2: FSMD Design Dr Le Dung Hanoi University of Science and Technology Exercise Thiết kế Datapath. ..Example 1: Datapath design (2) • Connect outputs of registers and counter to input of functional units • Connect output of functional units to input of registers and counter input sum; FOR i = 1 TO 5 input x; sum... (x> 10) then cnt=cnt + 1; sum=sum + x; end if; until x =0; output sum; output cnt; Chú ý: 1 0 ≤ x ≤255, 0≤ sum ≤255 Các lệnh viết trên cùng 1 hàng được thực hiện song song 2 Chỉ rõ các thanh ghi trong datapath là bao nhiêu bit Dr Le Dung Hanoi University of Science and Technology