Hey there,
hoping someone can clarify this for me. Assume I have three symbols: 1) a 3V3 supply symbol used to attach to nets that should be 3V3; 2) a regulator symbol that is the source of 3V3; and 3) an IC whose VCC pin should be powered by 3V3.
In each of the three cases, what pin direction should I be using in my library? The options are Pwr, Sup and Out.
Thanks.
Take a look at some Eagle libraries to see how Eagle does things. For example "74xx-us.lbr", part "74*00.dev". Its "VCC" pin and its "GND" pin both have a direction of "PWR". In "v-reg.lbr", the 3 pin regulators are done a bit differently: the "IN" pin's direction is "IN", the "GND" pin's direction is "IN", and the "OUT" pin's direction is "OUT".sjalloq:
Hey there,hoping someone can clarify this for me. Assume I have three symbols: 1) a 3V3 supply symbol used to attach to nets that should be 3V3; 2) a regulator symbol that is the source of 3V3; and 3) an IC whose VCC pin should be powered by 3V3.
In each of the three cases, what pin direction should I be using in my library? The options are Pwr, Sup and Out.
Thanks.
HTH
-Dave Pollum
I would have thought that “In” and “Out” are meant to refer to signal pins on logic devices, not to the direction of electrons flowing through power devices.
Admittedly I’ve been doing this for all of three days, but as I’m designing parts, I wouldn’t dream of using “In” and “Out” to refer to the Vin and Vout pins of a voltage regulator.
Sylvie - Well, looking at my libraries (not the Eagle libs), the voltage regulator output pins are "PWR" and so is GND,but Vin is "IN". I'm not sure why I did it that way. For your 3-terminal regulators, are all of the pins "PWR"?sylvie369:
I would have thought that “In” and “Out” are meant to refer to signal pins on logic devices, not to the direction of electrons flowing through power devices.Admittedly I’ve been doing this for all of three days, but as I’m designing parts, I wouldn’t dream of using “In” and “Out” to refer to the Vin and Vout pins of a voltage regulator.
-Dave
Well, they’re all PWR when I set them to be .
When I look at the devices in the VReg library (at least the one that I have), they have the Vin and Gnd pins marked as “In”, and the Vout marked as “Pas”.
Is there some convention for this that I’m violating?
What are Pas, Hiz, Sup, and OC supposed to be used for?
Am I going to get myself into trouble making all Vreg pins on devices into “PWR”? Does the software do something with this somewhere?
The Pulsonix software I use has similar options for pins and the software can check that two outputs aren’t connected together, for instance. I don’t use it very often, though, and usually leave pins as “Undefined”. It does help one avoid making silly mistakes, of course. Eagle can do similar checks, presumably.
Some of the Eagle options are obvious - OC is open-collector - but others aren’t. They should be described in the documentation.