• Previous message: Jeff Sondeen: "magic won't output .strm layer > 200"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Dear Michael,

> I noticed someone complaining about this being
> restricted to < 200.
> 
> In calmaInt.h I have CALMA_LAYER_MAX 255
> I put this in a year or so ago for TSMC, and I
> do not think I needed to change anything else.
> The layer number is stored in an int, but it maybe
> that when GDS is written there is a restriction.
> But, I seem to recall the GDS field is also 32 bits...

I checked around on the web, and found only confusion on the issue:

http://www.artwork.com/gdsii/asm3500/optical/optical_design3.htm

"MAX LAYERS
   Determines the heighest layer number
   allowed in the GDSII file. The standard value
   is 63. However, many CAD systems support
   up to 255 layers. You should leave this
   value at 63 unless you are sure that your
   target system can accept more. The maximum
   value you can set is 1024."

http://www.artwork.com/gdsii/gds2ascii/doc.htm

"NOTE: N must be at least 2 and not more than 200 to adhere to the
   original GDSII spec... GDS2ASCII supports a max N of 8191."

http://www.xs4all.nl/~kholwerd/interface/bnf/gdsformat.html

"13  0D02  LAYER  Two-Byte Signed Integer  layer number of element:
   Contains two bytes which specify the layer. The value of the layer
   must be in the range of 0 to 255."

http://www.nnf.cornell.edu/SPIEBook/spie9.htm

"Portions of the GDSII Stream Format Manual, Documentation No. B97E060,
   Feb. 1987, reprinted with permission of Cadence Design Systems, Inc.,
   555 River Oaks Parkway, San Jose, CA 95134.
   LAYER [0D02] Two-byte signed integer: contains the layer number. The
   value must be from 0 to 63."

http://www.buchanan1.net/stream_description.shtml

"0x0d  LAYER  0x02 INTEGER_2  Layer specification. On GDSII this
   could be 0 to 63, LTL [Integrated Silicon Systems, Inc. open
   architecture database] allows 0 to 255. Of course a 3 [sic] byte
   integer allows up to 65535..."

I hope this clears things up!  :)

						---Tim

• Next message: Vinayak Hegde: "subscribe"
• Previous message: Jeff Sondeen: "magic won't output .strm layer > 200"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]