FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Topics

16 x 16 multiplier example.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

The FPGA design process

Translation from HDL.– (synthesis, translation)

Logic synthesis.– (mapping)

Placement and routing.– (place and route)

Configuration generation.– (program file generation)

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Design experiments

Synthesize with no constraints. Synthesize with timing constraint.

– Tighten timing constraint. Synthesize with placement constraints.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Post-translation simulation model

HDL model in terms of FPGA primitives. Example: X_LUT4 \p12_Madd__n0015_Mxor_Result_Xo<1>1 ( .ADR0(x_7_IBUF), .ADR1(y_13_IBUF), .ADR2(c12[7]), .ADR3(row12[8]), .O(row13[7]) );

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Mapping report

Design Summary--------------Number of errors: 0Number of warnings: 0Logic Utilization: Number of 4 input LUTs: 501 out of 1,024 48%Logic Distribution: Number of occupied Slices: 255 out of 512 49% Number of Slices containing only related logic: 255 out of 255 100% Number of Slices containing unrelated logic: 0 out of 255 0% *See NOTES below for an explanation of the effects of unrelated logicTotal Number 4 input LUTs: 501 out of 1,024 48%

Number of bonded IOBs: 64 out of 92 69%

Total equivalent gate count for design: 3,006Additional JTAG gate count for IOBs: 3,072Peak Memory Usage: 64 MB

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Static timing analysis report

Timing constraint: TS_P2P = MAXDELAY FROM TIMEGRP "PADS" TO TIMEGRP "PADS" 99.999 uS ;

20135312 items analyzed, 0 timing errors detected. (0 setup errors, 0 hold errors)

Maximum delay is 20.916ns.---------------------------------------------------------------

-----------------

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Static timing report: delays along paths

Data Sheet report:-----------------All values displayed in nanoseconds (ns)

Pad to Pad------------------+----------------------+-----------+Source Pad |Destination Pad| Delay |------------------+----------------------+-----------+x<0> |p<0> | 5.824|x<0> |p<10> | 10.675|x<0> |p<11> | 11.214|x<0> |p<12> | 11.753|

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Routing report

Phase 1: 1975 unrouted; REAL time: 11 secs

Phase 2: 1975 unrouted; REAL time: 11 secs

Phase 3: 619 unrouted; REAL time: 12 secs

Phase 4: 619 unrouted; (0) REAL time: 12 secs

Phase 5: 619 unrouted; (0) REAL time: 12 secs

Phase 6: 619 unrouted; (0) REAL time: 12 secs

Phase 7: 0 unrouted; (0) REAL time: 12 secs The NUMBER OF SIGNALS NOT COMPLETELY ROUTED for this design is:

0

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Static timing after routing

Timing constraint: TS_P2P = MAXDELAY FROM TIMEGRP "PADS" TO TIMEGRP "PADS" 99.999 uS ;

20135312 items analyzed, 0 timing errors detected. (0 setup errors, 0 hold errors)

Maximum delay is 38.424ns.---------------------------------------------------------------

-----------------

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Timing constraint

Use timing constraint editor:

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Post-map static timing report

Timing constraint: TS_P2P = MAXDELAY FROM TIMEGRP "PADS" TO TIMEGRP "PADS" 32 nS ;

20135312 items analyzed, 0 timing errors detected. (0 setup errors, 0 hold errors)

Maximum delay is 20.916ns.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Post-routing static timing report

Timing constraint: TS_P2P = MAXDELAY FROM TIMEGRP "PADS" TO TIMEGRP "PADS" 32 nS ;

20135312 items analyzed, 0 timing errors detected. (0 setup errors, 0 hold errors)

Maximum delay is 31.984ns.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Tighter timing constraints

Tighten requirement to 25 ns. Post-place-route timing report:

Timing constraint: TS_P2P = MAXDELAY FROM TIMEGRP "PADS" TO TIMEGRP "PADS" 25 nS ;

20135312 items analyzed, 11 timing errors detected. (11 setup errors, 0 hold errors)

Maximum delay is 31.128ns.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Report on a violated path

Slack: -6.128ns (requirement - data path) Source: y<0> (PAD) Destination: p<30> (PAD) Requirement: 25.000ns Data Path Delay: 31.128ns (Levels of Logic = 31)

Data Path: y<0> to p<30> Location Delay type Delay(ns) Physical Resource Logical Resource(s) ------------------------------------------------- ------------------- K5.I Tiopi 0.825 y<0> y<0> y_0_IBUF SLICE_X2Y11.G4 net (fanout=31) 1.792 y_0_IBUF SLICE_X2Y11.Y Tilo 0.439 c2<5> p0_Madd__n0017_Mxor_Result_Xo<1>1 SLICE_X2Y11.F4 net (fanout=2) 0.304 row1<6> SLICE_X2Y11.X Tilo 0.439 c2<5> p1_Madd__n0019_Cout1 SLICE_X5Y16.F3 net (fanout=2) 0.784 c2<5> SLICE_X5Y16.X Tilo 0.439 c3<5> p2_Madd__n0019_Cout1 SLICE_X2Y18.G4 net (fanout=2) 0.668 c3<5> SLICE_X2Y18.Y Tilo 0.439 row5<4> p3_Madd__n0019_Mxor_Result_Xo<1>1

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Power report

Power summary: I(mA) P(mW)----------------------------------------------------------------Total estimated power consumption: 333 --- Vccint 1.50V: 0 0 Vccaux 3.30V: 100 330 Vcco33 3.30V: 1 3 --- Inputs: 0 0 Logic: 0 0 Outputs: Vcco33 0 0 Signals: 0 0 --- Quiescent Vccaux 3.30V: 100 330 Quiescent Vcco33 3.30V: 1 3

Thermal summary:---------------------------------------------------------------- Estimated junction temperature: 36C Ambient temp: 25C Case temp: 35C Theta J-A: 34C/W

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Power report: decoupling capacitance

Decoupling Network Summary: Cap Range (uF) #----------------------------------------------------------------Capacitor Recommendations: Total for Vccint : 4 470.0 - 1000.0 : 1 0.0100 - 0.0470 : 1 0.0010 - 0.0047 : 2 ---Total for Vccaux : 4 470.0 - 1000.0 : 1 0.0100 - 0.0470 : 1 0.0010 - 0.0047 : 2 ---Total for Vcco33 : 10 470.0 - 1000.0 : 1 0.470 - 2.200 : 1 0.0470 - 0.2200 : 2 0.0100 - 0.0470 : 3 0.0010 - 0.0047 : 3

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Improving area

Floorplanner window:

LEs

Chipfloorplan

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Rat’s nest wiring

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Routing editor view

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Adding placement constraints

Must add attributes to the Verilog:

// synthesis attribute rloc of p0 is X0Y0

multrow p0(row0,x,y[1],y[0],c0,row1,c1);

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Editing constraints

Use constraints editor to place constraints:

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Design browser pane

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Drag and drop constraints

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Change the shape of constraints

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Full set of placement constraints

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Placement results

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

New timing report

After placement constraints: 19742142 items analyzed, 0 timing errors

detected. (0 setup errors, 0 hold errors)

Maximum delay is 29.934ns. Compares to 31 ns for unconstrained

placement.

FPGA-Based System Design: Chapter 4 Copyright 2004 Prentice Hall PTR

Detailed routing constraints