Spin Stamp Micro-controler and Boebot?

Eric at Sac State

I would feel better if the product information directly said, you can plug the Spin Stamp
Micro-controller right into the Boebot?

I see that the stamp does contain a 3.3 volt voltage regulator, but I did not understand exactly
what voltage this would regulate.

Would this mean that VDD on my board of education board would now change to 3.3 volts?

I understand that if I am inputting a five volt signal into the propeller chip that I need a 1k
resister, in as a buffer.

But I am wondering about all the servo motors, if I can still send them pulse out signals, or if
these pulses will be coming at a lower voltage, and not work correctly, and I am also wondering
about how well my PNG sensor is going to work, with a change over from basic stamp to spin stamp?

I looked at the really long thread about the difference between 5 and 3.3 volt connections but could
not find a specific mention of the spin stamp micro-controller?

Bergamot

Eric at Sac State said...
I see that the stamp does contain a 3.3 volt voltage regulator, but I did not understand exactly
what voltage this would regulate.

Would this mean that VDD on my board of education board would now change to 3.3 volts?

It regulates the voltage coming into the propeller (and therefore the voltage coming out of the pins, if any). Everything else on the BOE stays 5V.

Eric at Sac State said...
But I am wondering about all the servo motors, if I can still send them pulse out signals, or if
these pulses will be coming at a lower voltage, and not work correctly, and I am also wondering
about how well my PNG sensor is going to work, with a change over from basic stamp to spin stamp?

Well the thing is, 3.3V is well over the threshold most 5V digital devices use (either 2.5V or 1.5V), so generally you don't have to worry about that.

Mike Green

The reason why Parallax doesn't have much documentation on the use of the Spin Stamp with BS2 boards like the BOE is that it's not a direct replacement for the BS2 series Stamps. Specifically, the I/O pins are 3.3V logic and can be damaged by direct connection to 5V logic devices. It's fairly easy to interface the two logic levels, but it takes some understanding of what you're connecting to. The long thread on 3.3V to 5V logic interfacing applies to the Spin Stamp just as it applies to other Propeller applications.

Regarding specific cases. You can connect a servo control line via a 1K resistor to a Propeller I/O pin (including the Spin Stamp). You can also connect a PING's control line via a 1K resistor to a Propeller I/O pin. BoeBotBasic, in the Object Exchange, is a special version of FemtoBasic for use with a BoeBot chassis. The copy in the Object Exchange is set up for use with a Protoboard, but it was originally developed using a Spin Stamp on a stock BoeBot. You just have to recompile it with _CLKFREQ = 10_000_000 and _CLKMODE = XTAL1 + PLL8X since the clock crystal on the Spin Stamp is different from the supplied clock crystal on the Protoboard. BoeBotBasic has routines for supporting 3 servos (two wheel servos plus a PING bracket servo), a PING, and IR emitter/detectors.