Sup and Pwr pins genera ting ERC warnings

On 28/09/16 19:59, Karl Lautman wrote:

I'm running Eagle 4.16 in Win7 x64.  I've created a number of parts and

assigned Pwr to their Vcc and GND pins.  In my schematic I name these VCC

and GND and then place +5V and GND symbols from the supply1 library and

name them VCC and GND (see attachment).  Nevertheless, when I run ERC I get

a warning like the following:

 

WARNING: Sheet 1/4: POWER Pin U$5 10_VCC connected to VCC

WARNING: Sheet 1/4: POWER Pin U$5 11_GND connected to GND

 

 

If I change the Pwr pins to Sup I get an overwritten warning instead, but

it's still a warning.  What am I doing wrong?

 

You've included the pad number in the pins' names. Why? Even if you

don't care about the possibility that the device might come in different

packages with different pin numbering (very common on devices that have

pins called "PE6"), doing so is an unnecessary duplication. It also

means your power pins are not called "VCC" and "GND" so you will get

warnings about connecting them to a net with a different name.

Fix your library parts (and while you're at it, assign an appropriate

PREFIX to them) and you'll be able to lose those warnings.

On 28/09/16 19:59, Karl Lautman wrote:

I'm running Eagle 4.16 in Win7 x64.  I've created a number of parts and

assigned Pwr to their Vcc and GND pins.  In my schematic I name these VCC

and GND and then place +5V and GND symbols from the supply1 library and

name them VCC and GND (see attachment).  Nevertheless, when I run ERC I get

a warning like the following:

 

WARNING: Sheet 1/4: POWER Pin U$5 10_VCC connected to VCC

WARNING: Sheet 1/4: POWER Pin U$5 11_GND connected to GND

 

 

If I change the Pwr pins to Sup I get an overwritten warning instead, but

it's still a warning.  What am I doing wrong?

 

You've included the pad number in the pins' names. Why? Even if you

don't care about the possibility that the device might come in different

packages with different pin numbering (very common on devices that have

pins called "PE6"), doing so is an unnecessary duplication. It also

means your power pins are not called "VCC" and "GND" so you will get

warnings about connecting them to a net with a different name.

Fix your library parts (and while you're at it, assign an appropriate

PREFIX to them) and you'll be able to lose those warnings.

You've included the pad number in the pins' names. Why?

For such a big package it's easier for me to associate a pin on-screen with

a pin on the datasheet if it's numbered on-screen.  More importantly, if I

take the number away, the library editor won't let me give two pins the

same name (e.g. VCC).

--

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On 28/09/16 22:16, Karl Lautman wrote:

You've included the pad number in the pins' names. Why?

 

For such a big package it's easier for me to associate a pin on-screen with

a pin on the datasheet if it's numbered on-screen.

That's a very poor reason, and one I totally disagree with. The pin

numbers of a TQFP64 (or bigger) are of absolutely no interest to me

while I'm designing the schematic, because the data sheet refers to

everything by its function / name throughout. Indeed, the last several

big devices I've worked with all had datasheets that referred to a

family of devices in packages from QFN36 to BGA144, with every single

one using different pin numbering.

More importantly, if I

take the number away, the library editor won't let me give two pins the

same name (e.g. VCC).

 

Read the tutorial.

If you want two pins with the same function, there is a proper way to

name them. If you follow that convention, the one that Eagle is designed

to work with, then you'll find it works a lot better.