Vdd is the voltage imput to whatever chip you are powering, on the Basic Stamp its 5 volts, and on the Propeller its 3.3 volts, you don't want to········· exceed these voltages at all, and you only want to be a tenth or two low at the most.·
Vin is the voltage input from your power supply·to·the voltage regulator·on the board that is used to regulate Vin down to Vdd for th·chip.
Vin·can·be a range of voltages that the regulator can tolerate, most of the Parallax regulators can deal with 6 to 9, or 6 to 12 volts.·
Vss is system ground, and you want all of your ground points tied to Vss, or the circuit won't work properly if at all.· These terms can get a lot more involved but this will give you a good start on understanding them.· Hope this helps
Would it be possible for you to go into detail on how to Configure the voltage input to the board?
Im new to the bs2e world and am having a bit of trouble.
anything helps!
There's no configuration possible or necessary. Vin is just the input to the regulator. The Stamp boards use a 5V regulator and these can withstand well over 12V. The BS2pe module has its own voltage regulator on it that can also withstand well over 12V.
There's a "gotcha" involved though. The regulators work by converting excess voltage (power actually) into heat and the higher Vin, the more heat is produced. The amount of heat also depends on the amount of current drawn. If you have your Stamp drive an LED, the LED's power has to go through one of the regulators. One or two LEDs can draw more current than the Stamp module itself or the same amount of current used by a sensor. There's limited ability for the Stamp module and/or the on-board Stamp board regulator to shed its excess heat. At a certain point, the regulator will turn itself off to protect itself from damage and that'll cause the Stamp to reset / shutdown.
Best is to limit Vin to the range of 6V to 9V. If you must run the Stamp from a 12V supply, you'll have to be careful about the amount of heat generated (and the amount of current drawn).
The 6V is a practical minimum input voltage needed to maintain voltage regulation with a 5V output. It's closer to 5.5V actually, but that's only practical if you have a separately regulated 5.5V power source.
Vdd and Vss are terms used to describe the supplies used with CMOS devices. Vss refers to source-substrate voltage, or something of the sort, and Vdd is drain-something voltage.
Usually Vdd (AKA Vcc) is +5V or whatever your positive supply is, and Vss is common ground (0 volts), where the negative battery terminal is connected.
But I occasionally see modern schematics using Vss as the positive supply, which could be problemmatic at best.
It's always wise to study a schematic (or ask questions, as you are doing) thoroughly before hooking things up.
Thank you Duane, that's exactly where I saw it recently but couldn't recall. I hope you and I aren't working on exactly the same thing, but it's a distinct possibility...
Comments
Vdd is the voltage imput to whatever chip you are powering, on the Basic Stamp its 5 volts, and on the Propeller its 3.3 volts, you don't want to······· ·· exceed these voltages at all, and you only want to be a tenth or two low at the most.·
Vin is the voltage input from your power supply·to·the voltage regulator·on the board that is used to regulate Vin down to Vdd for th·chip.
Vin·can·be a range of voltages that the regulator can tolerate, most of the Parallax regulators can deal with 6 to 9, or 6 to 12 volts.·
Vss is system ground, and you want all of your ground points tied to Vss, or the circuit won't work properly if at all.· These terms can get a lot more involved but this will give you a good start on understanding them.· Hope this helps
Curt
·
·
Would it be possible for you to go into detail on how to Configure the voltage input to the board?
Im new to the bs2e world and am having a bit of trouble.
anything helps!
thanks
There's a "gotcha" involved though. The regulators work by converting excess voltage (power actually) into heat and the higher Vin, the more heat is produced. The amount of heat also depends on the amount of current drawn. If you have your Stamp drive an LED, the LED's power has to go through one of the regulators. One or two LEDs can draw more current than the Stamp module itself or the same amount of current used by a sensor. There's limited ability for the Stamp module and/or the on-board Stamp board regulator to shed its excess heat. At a certain point, the regulator will turn itself off to protect itself from damage and that'll cause the Stamp to reset / shutdown.
Best is to limit Vin to the range of 6V to 9V. If you must run the Stamp from a 12V supply, you'll have to be careful about the amount of heat generated (and the amount of current drawn).
The 6V is a practical minimum input voltage needed to maintain voltage regulation with a 5V output. It's closer to 5.5V actually, but that's only practical if you have a separately regulated 5.5V power source.
But I occasionally see modern schematics using Vss as the positive supply, which could be problemmatic at best.
It's always wise to study a schematic (or ask questions, as you are doing) thoroughly before hooking things up.
http://encyclobeamia.solarbotics.net/articles/vxx.html
Both Vss and Vdd are listed as synonyms for Vcc at Maxim! http://www.maxim-ic.com/glossary/definitions.mvp/term/Vcc/gpk/943
I was surprised a couple of weeks ago to see Vss as a positive supply. The L298N datasheet has this:
So why would anyone be confused? (Where's the sarcastic font?)