"#" symbol on sch.

[brew99]

What does this "#" symbol usually at the end of a signal name/function mean on a schematic?

Sorry just starting out looking at laptops for fun, and can't find this info

[bluestone]

Re: "#" symbol on sch.

Most at times it indicates a low signal, a signal to send another signal low e.g SUSP=3.3v but you need SUSP#=3.3V to make SUSP to be 0v

[BlueMidnight]

Re: "#" symbol on sch.

Logic signals (as opposed to power rails or data lines) communicate answers to simple questions. For example, SLP_S3# answers the question "Are we in an S3 or lower sleep/power state?

There are two possible answers (true/false). And to represent these it uses 2 possible voltages (often 0V/3V). But which voltage means "true" and which means "false"? That's what the '#' character tells you.

Plain signal name: 3V = True, 0V = False
Signal with a '#': 0V = True, 3V = False

Technically, the former is referred to as an "active high" signal, and the latter as an "active low" one. This is because the first one uses a high voltage to represent a true condition, while the second uses a low voltage to indicate the same thing.

Sometimes a different character is used rather than "#" (e.g. an "_L" suffix). But it shouldn't be too hard to figure out the method by just glancing around whichever schematic you are reading and using some common sense.

[brew99]

Re: "#" symbol on sch.

Thanks for that detailed explanation. That really helps

[Techtiger]

Re: "#" symbol on sch.

Logic signals (as opposed to power rails or data lines) communicate answers to simple questions. For example, SLP_S3# answers the question "Are we in an S3 or lower sleep/power state?

There are two possible answers (true/false). And to represent these it uses 2 possible voltages (often 0V/3V). But which voltage means "true" and which means "false"? That's what the '#' character tells you.

Plain signal name: 3V = True, 0V = False
Signal with a '#': 0V = True, 3V = False

Technically, the former is referred to as an "active high" signal, and the latter as an "active low" one. This is because the first one uses a high voltage to represent a true condition, while the second uses a low voltage to indicate the same thing.

Sometimes a different character is used rather than "#" (e.g. an "_L" suffix). But it shouldn't be too hard to figure out the method by just glancing around whichever schematic you are reading and using some common sense.

Thanks for the technical explanation

[Techtiger]

Re: "#" symbol on sch.

Most at times it indicates a low signal, a signal to send another signal low e.g SUSP=3.3v but you need SUSP#=3.3V to make SUSP to be 0v

Thanks