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mashersmasher
04-23-2007, 10:01 PM
so i got an ancient version of this board from ebay. unlike this one mine has no capacitors and i was wondering whether that would cause a problem or reduce the live of my bs2. also does it need a voltage regulator like the kind on the boe board to prevent burnout? last question, has anyone successfully overclocked there basic stamp 2 and would it serve any purpose?
http://www.parallax.com/detail.asp?product_id=27120

mashersmasher
04-23-2007, 10:07 PM
oh and another question. if i use 12v from 4 aa batteries on ether the BOE or bs2 Carrier Board will it cause harm to eather the stamp or the board? are there any modifications i can do to make them function on 12v without burnout? the reason is i want to use 12v on motors i have for a robotics project and i want to avoid having 2 power sources or adding another voltage regulator

Mike Green
04-23-2007, 10:34 PM
The capacitors are there to allow you to use the serial connector for data. When you open a serial port on a PC, the DTR line is made active. This resets the Stamp. Without the capacitors, this reset lasts until the serial port is closed ... not very usable. I suggest you add them ... it's easy enough to do.

The Stamp has a regulator on it's substrate. This regulator has a little excess capacity which you can use for your circuit. Check the Stamp Manual for details. If you're going to need more power than what this regulator can supply, you'll need another one installed on the board.

Regarding overclocking ... It would be a waste of a perfectly good Stamp. You are likely to break the Stamp itself trying to remove and replace the resonator and it would change all the timings. Whether the Stamp would still work afterwards is anyone's guess.

All of the Stamps are designed to use a Vin up to 12V. Keep in mind that anything above 5V must be dissipated as heat and the regulator on the Stamp substrate is limited in how much it can dissipate. If you use any significant amount of current from the on-Stamp regulator to power other devices, you may have to limit the Vin to keep the heat dissipation within reason.

Chris Savage
04-23-2007, 11:34 PM
mashersmasher said...(trimmed)
unlike this one mine has no capacitors and i was wondering whether that would cause a problem or reduce the live of my bs2. also does it need a voltage regulator like the kind on the boe board to prevent burnout?
Hello,

ˇˇ The capacitors are there to block DC on the DTR line.ˇ The problem is somewhat rare on PCs but we have seen it especially on some Dell computers.ˇ When the Serial Port is idle the DTR line is held high, effectively holding the BASIC Stamp in a reset state.ˇ The capacitors block the DTR and allow only a single pulse through (like edge triggering) during the normal reset which occurs during programming or identification.ˇ You will know if you need them by writing a single program to blink an LED.ˇ If it doesn't run without unplugging your programming cable then you have that issue.ˇ A possible work-around though is to include a DEBUG line at the beginning of the program which will cause the port to remain open to the BASIC Stamp Editor and your program would run normally.


mashersmasher said...(trimmed)
oh and another question. if i use 12v from 4 aa batteries on ether the BOE or bs2 Carrier Board will it cause harm to eather the stamp or the board?
If your 4AA batteries are producing 12V you may have a power problem.ˇ 4AA batteries ˇshould produce ~6VDC.

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Chris Savage
Parallax Tech Support

mashersmasher
04-24-2007, 01:28 AM
sorry my bad i meant 8 aa's

thanks for the help everyone

mashersmasher
04-24-2007, 01:38 AM
oh and sorry to double post but which way does the bs2 go in the Carrier board? big chip facing the serial port?