X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sbcglobal.net; s=s2048; t=1437265911; bh=wzrpgIhsrbZM8w3EAg+vrm96BSMM+U4WH3Cd21/qT/8=; h=Date:From:To:Subject:References:In-Reply-To:From:Subject; b=tYpWcsDpT6A3G3a9zPP5bGgr9OVjmiXQviXw0PlkXMp2fzgNRaWFPKs+F6L+IRAEUjahuUAKiAbEcXNtok/oeWEJO4Ew+9DgFGBJ6rZMBOUiE5KgOSH1TFBm9TLoLFqB1wXYZFvAC9Po5PsmPcV7jrXWv35lRegNqs9bF2fWoVyzOEeazGgnXbxxx4eePgySfHTvUZO4DozsVPzVX9CsLFWIzkEO9ZIxzCJ/2cGR8QlQwDN0+YytRb4kbFaiXllxQLzovd44UFv5lZ83s12QZyeSF/eVdfN22zr9QyQyKQJ/mFgrit9hccnqPvYVF7Rge+7dyZqPGVXFLaBiHUToaA== X-Yahoo-Newman-Id: 591498 DOT 32054 DOT bm AT smtp119 DOT sbc DOT mail DOT ne1 DOT yahoo DOT com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: PWXHpS8VM1mhN.194XKayqUVDkCSrmW2fAawlHI33q0RLK8 hT.dhSRugTRoI2KGoz2YyhDS2C6bziDReAF55TUJEagbRMlQBxoSaIKqCO5i ef704cWYQwzON8Azqr3Ptqk2Sea58MSsNDar9EbyXYEOPkvmZxU.fUhH5U2N XM1IcM.nNjW2sd3sX0xfVKRyF2fD86ww2C_MUPkGz2jBlbQ06PBLK.j0n84B NxyMYtofYRmj0OacEHpY23ExmOoEUj1eLKAEb8ORrjmKf55OCbwfgHKvsPei 0ys3GZQucoUeoEzOY85YNRwWMHeXTs3WFnr72K53TTpOIFcBj6zijlU7IeM3 IK4hJYP64B3YvcI9gOsh8siAZYcDOv2wUCcqLygR8HZnoz_MV93lMQiRssTy ocxYlB1CDSOo.wyPKZAm_IuO6NQyALwCOzGxu2oLAxMkk9ebWF_I.gva3zeo FUHdm3qF60Zm4eSXLstBBIQN9TlDA2ONJ.tWLe3_nNHq10XPwVPUq3Zj8UO9 _NEdU.CLSIBbCBoNKKaQm1iADeRAjk4OfnnOwiWFxHbdJ8Duznrg- X-Yahoo-SMTP: xaem6kSswBCHwCBMr0jlCBIQdXYGmRxsm8OX6ACyP7Ho9Sk- Message-ID: <55AAEF63.2060003@sbcglobal.net> Date: Sat, 18 Jul 2015 17:29:23 -0700 From: "Girvin R. Herr (gherr375 AT sbcglobal DOT net) [via geda-user AT delorie DOT com]" User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: geda-user AT delorie DOT com Subject: Re: [geda-user] Difference between attached and detached attributes References: <55A813B5 DOT 4040609 AT sbcglobal DOT net> <20150718234406 DOT GA14479 AT visitor2 DOT iram DOT es> In-Reply-To: <20150718234406.GA14479@visitor2.iram.es> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Reply-To: geda-user AT delorie DOT com On 07/18/2015 04:44 PM, Gabriel Paubert (paubert AT iram DOT es) [via geda-user AT delorie DOT com] wrote: > On Sun, Jul 19, 2015 at 12:09:52AM +0200, Roland Lutz wrote: >> On Thu, 16 Jul 2015, Girvin R. Herr (gherr375 AT sbcglobal DOT net) [via geda-user AT delorie DOT com] wrote: >>> I have been doing some symbol work in gschem and I got confused >>> again about attached attributes vs detached attributes. The >>> manuals do not go into detail about usage. Hint, hint. Can >>> someone tell me what is the difference between them and where I >>> should apply one vs the other? >> An attribute is a specially formatted text object which can be >> attached to a component, net, bus, or pin, or not be attached at >> all. >> >> An attribute which is not attached to an object is called a "floating" or >> "toplevel" attribute. Floating attributes are used for two purposes: in a >> symbol, they contain default attribute values. In a schematic, they >> contain information global to that schematic page; for example, the VHDL >> backend searches for a toplevel "module-name" attribute in the schematic, >> and John Doty's spice-noqsi backend searches for "spice-prolog" and >> "spice-epilog". >> >> An attribute which is attached to a component overrides the value from the >> symbol's floating attribute. (There are some exceptions to this like the >> "graphical=1" attribute which can't be properly unset by attaching an >> attribute to the component.) You can delete an inherited attribute by >> attaching an attribute with the value "unknown" to the component. >> >> You can't attach an attribute to a specific pin of a component's >> symbol, so you can't override pin attributes when you instantiate a >> symbol in a schematic. There is a special slotting mechanism, >> though, which allows you to select one of a set of pre-defined pin >> numbering schemes. >> >> It is important to understand that the attributes inherited from the >> symbol (both floating and attached to a pin) live in the symbol file, >> whereas the attributes attached to the component live in the instantiating >> schematic file. You don't have a way to change the symbol from the >> instantiating schematic; the way to change inherited attributes is to >> attach an attribute with the same name and another value to the component. >> (You could obviously change the symbol by embedding it and hacking the >> schematic file, but AFAIK, there is no way to do this in gschem.) >> >> When creating a component, some floating attributes from the symbol are >> usually copied to the schematic and automatically attached to the symbol, >> hiding the inherited attributes. This is called "attribute promotion". >> The default set of promoted attributes is: footprint, device, value, >> model-name, and symversion. >> >> The menu items "Attributes/Attach" and "Attributes/Detach" are used >> to attach floating attributes to components, nets, buses, and pins, >> and to convert attached attributes back to floating attributes. You >> don't need these for normal gschem usage. (If you still want to try >> them, take extra care not to accidentally lose invisible attributes. >> You can type "e n" to make invisible text temporarily visible.) > "e n" is a big hammer and often results in an extremely cluttered > display: if you select a component, typing "t t" will toggle the visibility > of the attributes of the component which is much less invasive. Typing > "t t" again obviously reverts the operation. > > Gabriel > Gabriel, That's a good tip. I made a note of it for future use. Thanks. Girvin Herr