ssh allows us to login to the system and “-x” enables x windows support “pwd” – print...

ssh allows us to login to the system and “-X” enables X Windows support

“pwd” – print working directory – should be your user directory“cd” – change directory into reference_design.

“ls –alrt” – list directory contents.

Other useful Linux commands:man

topmkdirpasswdcd ~ cd .. rmgrepmorecat

Type xclock and you should see a clock appear if X Windows is working properly - shown on your screen but running remotely.

Log in with Linux

cp –r ~grupo1/reference_design/ ~/.

This will create a directory structure.

RTL is where you should store your source verilog code.

SYN is where you will perform synthesis. Update the script “dc_good.tcl” in scripts and invoke “dc_shell –f dc_good.tcl | tee logs/output.dc”

PNR is where you will perform place and route. Update the script “icc_good.tcl” in scripts and invoke “ic_shell –f icc_good.tcl | tee logs/output.ic”

CUSTOM is where you store reference files. Eg: matlab files that create test vectors and expected results, simulation will use these vectors and match the results.

SIM is where you store your simulation files. Optional in this case.

GOLDEN is where you store your final files – RTL, GDS, SDC, TB.v, and scripts.

Copy the Reference Design

Simple reference designTwo counters – one clocked by external clock, the other by an internally generated clock. All clocks have to be identified for static timing to work correctly. Total of 40 flip-flops no where near the limit in terms of area for this chip size.

Only four outputs and two inputs, power and ground. Total is 8 pins.

Design Compiler - Reference Design

cd to syn directory for synthesisUpdate the script “dc_good.tcl” for your design

identify file and module nameidentify clocks and frequency

Run “dc_shell –f ” to invoke script. Look in reports for quality of output

This can be done in gui format as well – “dc_shell –gui”

Design Compiler - Prepare for synthesis

Design Compiler - Checking synthesis

During synthesis you should see output identifying all flip-flops. Make sure this make sense. I have two 20 bit counters in the reference design so this looks good.

Also look for latches which indicates a problem in your RTL. All if statements need an else and if missing can cause latches.

After script is run, look for returns of 1 for all lines. 0 is a failure for the previous command.In results you will have a *postsynth.v as your netlist and a sdc file with timing info.Check the netlist to make sure it looks reasonable.In logs, you will see the commands and output. Search for errors and “0’s”.In reports, check all files thoroughly.

Timing – check that critical path passes and is legitimate.Area – not too big. I will report numbers that are reasonable in class.Power is interesting but not very accurate. Power is data dependent but you can improve by adding switching data from the simulator VCS.

Design Compiler - After synthesis

Design Compiler - Checking synthesis

Top of the netlist should have your module name, IO’s and nets.

You will see some starting with a back slash which is an escape character as some tools cannot handle square brackets and this is used to escape.

Design Compiler - Checking synthesis

Tri’s will be inserted due to the IO’s being bidirectional.

Also, look at the gates. DCX1 is a flip-flop. Scroll down to check all of the gates.

Design Compiler - Checking synthesis

Pad_bidirhe are the IO cells and you should see other gates like NAND2X1.

NAND2X1 is the smallest 2 input NAND gate. X1 means small and the 2 is the number of inputs. A and B are in and Y is the output pins normally.

Design Compiler - Timing report

Worse case path for main clock.

Through the adder from bit 0 to bit 19 as expected. 20 nS to complete and finished in 8.34 nS so time to spare – which means positive slack of 11.27 nS.

Passed and made sense.

Design Compiler - Timing report

Worse case path for internally clocked counter.

Through the adder from bit 0 to bit 19 as expected. 20480 nS to complete and finished in 8.34 nS so time to spare – which means positive slack with over 20,000 nS of positive slack.

Passed and made sense.

Note that these timings are only for setup calculations and no holds are completed. Since the clock tree is not in place (ideal clock tree assumed) there is no clock skew which is required for hold violations.

Check for latches (should not exist) and that the basic numbers are expected.

For the MOSIS chip, I expect that 3-5 times this area is possible.

Design Compiler - Area report

IC Compiler - Place, route, timing and checks

The icc_good.tcl script will go into the synthesis directory to obtain the netlist and sdc file (timing).

IC Compiler – First return – Floor PlanAt first return – start_gui to invoke viewer.

You will need to run to this point twice: once just to create an IO file and once to use the file renamed to is_pad.tcl with the source uncommented.

cp set_pad_attributes_on_cell_xtal_chip_with_io.tcl is_pad.tcl

Check that the file has all IO declared.

Uncomment the “source is_pad.tcl” line in the script and run again.

IC Compiler – First return – Floor Plan

IC Compiler – First return – Floor Plan

Use the ruler to check sizes of the die. 1500 microns is the max size for each side.

IC Compiler – First return – Floor PlanChange the visibility selections to see different layers. Pins and Site rows to see metals and where the standard cells will be placed later. Note that all unplaced cells are to the right – out of bounds for now.

IC Compiler Second return – Power and IO Fill

IC Compiler Second return – Power and IO FillShould see power lines at all three levels and ring with vertical straps. IO Ring is complete but you must set the visual settings to “Max Quality”. Change levels to 1 or 2 to see into lower hierarchical levels. May need to change color of poly to see transistors.

IC Compiler Third Return – Placement of Cells

IC Compiler – Fourth Return - Clock Tree Invoke “Report Clock Tree”

IC Compiler – Fourth Return - Clock Tree

IC Compiler – Fourth Return - Clock Tree Selecting main_clock

IC Compiler – Fourth Return - Clock Tree Selecting “secondary_clock” – Note no IO included in this internal clock.

======================= Clock Tree Summary ========================Clock Sinks CTBuffers ClkCells Skew LongestPath TotalDRC BufferArea-----------------------------------------------------------------------------------------------main_clock 39 12 14 0.0493 2.0112 0 4536.0000second_clock 20 4 4 0.0311 0.9414 0 2016.0000 Post Routing (skew increased :/ ): ======================= Clock Tree Summary ========================Clock Sinks CTBuffers ClkCells Skew LongestPath TotalDRC BufferArea-----------------------------------------------------------------------------------------------main_clock 39 12 14 0.1113 1.9813 0 4536.0000second_clock 20 4 4 0.0319 0.9401 0 2016.00001

IC Compiler – Fourth Return - Clock Tree In 90nm technology, 0.2 ns of skew was considered acceptable. Skew isn’t a problem if you pass hold timings though.

IC Compiler – Fourth Return - Clock Tree Check timing report in log. Need “Met” next to slack.

IC Compiler – Fourth Return - Clock Tree Check QoR report for hold violations after the tree.

IC Compiler – Fifth Return - Routing

IC Compiler – Well filler

IC Compiler – Metal Density Fill

verify_pg_nets Checking [gnd!]: There are no floating shapes All the pins are connected. No errors are found.Checking [vdd!]: There are no floating shapes All the pins are connected. No errors are found.Checked 2 nets, 0 have ErrorsUpdate error cell ...1 verify_lvs ** Total Floating ports are 14.** Total Floating Nets are 0.** Total OPEN Nets are 0.** Total Electrical Equivalent Error are 0.** Total Must Joint Error are 0.

Check floating nets are on unused outputs of cells. This is ok.

Check the reports directory for timing and QoR reports for passing all timing checks including holds.

IC Compiler – Final Check Off

IC Compiler – Final Check Off

Check floating nets are on unused outputs of cells. This is ok.

IC Compiler – Final Check Off

Data_in and Data_inB from IO must float if they are output pins.IC Compiler – Final Check Off

Custom Designer – Import GDSGo to “custom” directory and invoke “cdesigner”, create a library, read in the GDS, add metal 3 art (optional) and run final DRCs.

We will be performing DRCs on the logic level and not check the IO’s as these are known to be good and have problems with DRC rules (on the to-do list to fix but just a minor annoyance now).

Before you run the DRCs - you can use “add net” after selecting “metal3” and add metal art work. This can be saved as a cell in the library.

Custom Designer – Create new libraryCreate “new library” to import stream the GDS into with the correct technology.

Custom Designer – Import GDSImport “stream” allows us to read in the GDS file created by IC Compiler and later to be sent to MOSIS for fabrication. The GDS shows all geometries of the fabricated device.

Custom Designer – File -> Import StreamIC Compiler script command: “save_mw_cel -as ${design_name}” determines the Top Cell.

IC Compiler script command:“write_stream -lib_name MW_${design_name}_LIB -format gds results/${design_name}.gdsdetermines the file name of the GDS filename.

Custom Designer – Open Layout

Custom Designer – Draw Images in Metal 3Shift F – shows all lower hierarchical layers.F – fits the design to the window.

Custom Designer – Draw Images in Metal 3Shift F – shows all lower hierarchical layers. This shows after shift F.

Custom Designer – Draw Images in Metal 3On the right you can select metal 3 and the glasses icon to only see Metal 3.Control R – redraws after a change.

Custom Designer – Draw Images in Metal 3On the right you can select create interconnect and draw lines. There is a submenu that allows you to change thickness and permitted angles.

Custom Designer – Run DRCsBefore we can run checks, we must flatten the design. Open Hierarchical Navigator.

Custom Designer – Run DRCsSelect flatten from edit menu.

Custom Designer – Run DRCsThere will be “flatten” submenu in the tool bar and set the switches according to the picture below.

With the mouse, select the entire design by dragging a box around everything.

Then click the check mark on the far right of the menu.

You should see only one instance with sub-instances in the Hierarchical Navigator after you click on the refresh.

Custom Designer – Run DRCsUse the verification menu to run final DRCs regardless of whether you added any metal patterns. Only select the core and avoid the IO’s as there is an issue with the rules for the cells which isn’t real.

Custom Designer – Run DRCsUse the verification menu to run final DRCs regardless of whether you added any metal patterns. Only select the core and avoid the IO’s as there is an issue with the rules for the cells which isn’t real.

Custom Designer – Run DRCFill in the following fields of the DRC setup pane – “Main”. The runset file should be in your custom directory. Press the refresh button next to runsets.

Custom Designer – Run DRCIf you press the refresh button in the Main panel next to the runsets, you should see fields in this “control variable” section. There are none in this picture as Hercules (DRC checker) was not yet installed.

Custom Designer – Run DRCIn Custom Options, click the “select window” button and you will be allowed to select from the main window what will be DRC checked. Since there are problems in the IO that are not real DRCs and the IO’s are proven, we are only going to check the interior section of the chip. Select the interior by drawing a box around the chip but avoiding the IO rings. Coordinates will show in the field and should be similar to what is shown here – approximately 250, 1250, 1250, 1250.

Now click OK to run DRCs.

Custom Designer – Run DRCs

Run density_check.bash script on gds file.

MOSIS Submission Tutorial for ON Semiconductor 0.5u C5F CMOS

Exampledesignandproject details

OverviewAfter being assigned a design name, number and password go to:

www.mosis.com

Select “fabricate request” and fill in the form for the secure https upload option

Put your five digit number and password here.

Use your design number

Run the crc program on your gds for thesetwo numbers

Use your email address, phone number and design.

Put any information that will make receiving the chips easier