Once the Advanced Autorouter has completed, a report is generated, this page details the report headings and sections.
Advanced Router Routing Strategy Overview
Essentially, the table lets you know the performance at each stage of the process. Each of the processes relates to a check box on the router dialog.
Initially the router checks for multiple nets following similar paths, as you would get with data and address busses, and attempts to route those first if any are present because they will have the biggest impact on real estate requirements. Next in the fanout stage, the router tries to route congested areas with stub tracks away from the components to ensure that subsequent routing is less likely to block access to pads, nets to power and ground layers for example. Now the main routing takes place, with the reduction in errors against the previous pass being reported at each stage.
Having completed as much of the routing as possible, the program moves onto the cleaning stage. This is the tidying of the routes, with particular emphasis on via reduction. Again, several passes are typically used as the tidying at one point might affect other areas. Finally, the recorner stage is where mitres will be added if selected, and redundant corners removed as far as possible. The board is then released back to the program and the report written.
Advanced Router Report Strategy Columns
Within the routing report, columns under the Algo (Algorithm) header specify the routing algorithm that was used and the results.
Bus
Invokes a ‘colinear pins’ routing pass only on regular array of pins with collinear connections where the pins share a common X or Y coordinate. This is particularly effective on memory arrays. In this mode, the router will not generate conflicts, so rules must allow for sufficient space. By default, traces are routed orthogonally, unless the diagonal option is specified.
Fanout
Fanout This invokes a number of passes that routes short escape tracks to vias from SMD pads. This can be controlled by changing values in the Rules option. You can specify the number of passes that you want.
Route
This is the number of routing passes which you have defined for routing. This will be either all nets in the design or the specified nets depending on how you set it. There is a trade-off for the number of passes against the time it will take to complete. A large design will need more passes but will also take longer to route. It may be that by reducing the number of passes and not possibly achieving a 100% result, it will take a lot less time but you can complete the remaining routes by hand. It using the Load Results After Each Pass option, you can visually monitor the routing after each pass to check its progress.
If it routes to 100% before the number of specified passes then no more passes will be attempted.
Filter
If the Routing does not achieve 100% because of crossing conflicts then the Filter passes will try to improve the completion by removing as many of the conflicts that it can. You can specify the number of passes that you want.
Clean
The Clean pass has been specified using the Optimising re-routing passes that attempts to reduce the number of corners, vias, off centre pad entry and more SMD pad exits on the long side. You can specify the number of passes that you want.
Recorner
The Recorner pass has been specified by Mitre and changes 90 degree corners to 135 degree corners to decrease the overall length of tracks. It is performed on wire corners exiting pins and vias, as well as bend and slant wire configuration.
Advanced Router Report Headers
Across the report are headers which define the actual results of the router for each strategy pass:
- # This is the pass number and will be sequential.
- Shorts The router is allowed to deliberately create shorts between routes as it performs its algorithm. These conflicts will be resolved on later passes. It is normal to see these reduce in number as more passes are completed. If you notice these are high but do not reduce, then the chances are, the conflicts cannot be resolved.
- DRC Errs As with Shorts, the router is allowed to create DRC errors of tracks against other tracks or obstacles. these get resolved during subsequent passes.
- Failures Reports a net that has been attempted during this pass but has either failed instantly because of DRC errors, or has been tried and rejected because it has exceeded the routing cost.
- Unwired This is the number of connections that remain unrouted.
- Vias This is the number of vias in the design as the router operates on each pass.
- %Red This is the percentage completion of the router. Ideally, a 100% completion is the best outcome.
- Time This is the time taken by each pass and is not cumulative.
- Total This is the total time taken by each pass and is cumulative as the router runs each pass.
Advanced Router Report Results
A typical report might look like this:
Router Report
-------------
Report Written: Thursday, February 18, 2021
Design Path: C:\Designs\Current\P9981\PCB\9981-1.pcb
Design Title:
Created:
Last Saved: 18/02/2021 10:33:42
Editing Time: 1066 min
Units: mm (precision 3)
Nets = 48
Components = 75
Connections = 135
Vias = 5
Routed Length = 6866.300 mm
Signal Layers = 2
Power Layers = 0
Total Pins = 183
Completion = 100.00%
Unroutes = 0
Routing Time = 00:00:02
____________________________________________________________________________________________
| | | | | | | | | | |
| # | Algo | Shorts |DRC Errs|Failures|Unwired | Vias | %Red | Time | Total |
|_____|__________|________|________|________|________|________|________|_________|_________|
| 1| Bus | 0| 0| 0| 135| 0| | 0:00:00| 0:00:00|
| 2| Fanout | 0| 0| 0| 135| 0| | 0:00:00| 0:00:00|
| 3| Route | 23| 0| 3| 3| 5| 0| 0:00:00| 0:00:00|
| 4| Route | 19| 0| 0| 0| 7| 17| 0:00:00| 0:00:00|
| 5| Route | 11| 0| 0| 0| 4| 42| 0:00:00| 0:00:00|
| 6| Route | 4| 0| 0| 0| 7| 63| 0:00:01| 0:00:01|
| 7| Route | 0| 0| 0| 0| 9| 100| 0:00:00| 0:00:01|
| 8| Filter | 0| 0| 0| 0| 9| 0| 0:00:00| 0:00:01|
| 9| Clean | 0| 0| 4| 0| 7| | 0:00:00| 0:00:01|
| 10| Clean | 0| 0| 3| 0| 5| | 0:00:00| 0:00:01|
| 11| Clean | 0| 0| 3| 0| 5| | 0:00:01| 0:00:02|
| 12| Clean | 0| 0| 3| 0| 5| | 0:00:00| 0:00:02|
| 12| Recorner | 0| 0| 0| 0| 5| | 0:00:00| 0:00:02|
|_____|__________|________|________|________|________|________|________|_________|_________|
End Of Report.