Prop proto board versus basic stamp.

jeffjohnvol

I've been working with a bs2px stamp on my current project because I needed something that would work with the PLC product (I needed 24 volt i/o). But when bored at work, I read the forums and the product guides etc.

I was looking at the propeller proto board for around $20. And it has the chip and crystal already on it ready to run. Incredible. So.... my question is, is there any benefit to using a stamp over the propeller other than pbasic? Looking at spin, I think I would prefer that because I prefer functions over goto/gosub anyway.

I realize there is an additional initial cost for the prop plug, but that’s small compared to the price of a stamp plus a development board.

I'm assuming that each cog of the propeller is faster than the stamps, or is that an incorrect assumption?

Are there any advantages of the stamp over the propeller?

Also, can anyone tell me that if I were to interface a 1302 or 1307 timekeeping chip, would I be able to share the same crystal/clock on the protoboard?

StefanL38

hello jeffjohnvol,

i know the basicstamp only a little bit. The main difference is the greater flexability of the propeller.
Whenever you need a driver for whatever or anything is timecritical you dedicate a cog to this job
and its working.

There are a lot of ready to use codes in the object exchange.

There is already one for the DS1302 obex.parallax.com/objects/89/

Yes SPIN allows a very structured way of programming with its objects.

Loops and lines - belonging to if or case statements - are defined by indention.
There is no other way so the IDE makes everybody program in a formatted way

best regards

Stefan

Mike Green

1) Each (Stamp vs. Propeller) has advantages and disadvantages. The Propeller is much faster than the Stamp and has much more memory available for program and data. It has 8 processors including independent timers and video generators vs. the single processor of the Stamp and has 32 I/O pins vs. the 16 I/O pins of all the Stamps except the BS2p40. On the other hand, the Stamps are simpler, easier to learn, more than adequate for many applications, and have a much larger pool of sample code, tutorials, and other educational material. The Propeller is a 3.3V device and, although more and more devices on the market are 3.3V, a lot of existing devices are 5V only and some interfacing has to be done.

2) The real time clock chips usually require a 32768Hz crystal mounted close to the chip and you can't place extra loads on it. It doesn't make sense to run the RTC chip off the Propeller's clock, not the least of which is that the RTC is expected to have a backup battery while the Propeller would normally be shut off from time to time. If the Propeller is not going to be shut off, why not have the Propeller keep track of the time and date?

jeffjohnvol

Mike Green said...
1) Each (Stamp vs. Propeller) has advantages and disadvantages. The Propeller is much faster than the Stamp and has much more memory available for program and data. It has 8 processors including independent timers and video generators vs. the single processor of the Stamp and has 32 I/O pins vs. the 16 I/O pins of all the Stamps except the BS2p40. On the other hand, the Stamps are simpler, easier to learn, more than adequate for many applications, and have a much larger pool of sample code, tutorials, and other educational material. The Propeller is a 3.3V device and, although more and more devices on the market are 3.3V, a lot of existing devices are 5V only and some interfacing has to be done.

2) The real time clock chips usually require a 32768Hz crystal mounted close to the chip and you can't place extra loads on it. It doesn't make sense to run the RTC chip off the Propeller's clock, not the least of which is that the RTC is expected to have a backup battery while the Propeller would normally be shut off from time to time. If the Propeller is not going to be shut off, why not have the Propeller keep track of the time and date?

1) good point about the 3.3v driving of outputs.· I hadn't considered that.· Sounds like there are a little·more interfacing requirements for the prop.· Still though, for the money it seems to be a no-brainer to me to use the prop.·

2) another good point.· When Chris Savage mentioned he adds a 1302 to each of his stamp projects for the RAM alone if nothing else, I just made an assumption that I would want it for the prop.· I haven't searched, but I take it there is built in time keeping abilities in the prop, or code written for it already?

Mike Green

The Propeller Protoboard is a really good price for the capabilities

The Propeller normally runs off a crystal (5MHz on the Protoboard) and, once a program is running, the CNT register (see the Manual) keeps track of system clock cycles since the last power on (modulo 32 bits). You would need to devote a cog to using this as a time "tick" and keeping an actual time and date since, with an 80MHz system clock (commonly used), a 32 bit count rolls over in less than a minute. It's not hard to do.

Rayman

Somebody just pointed out a trick to use both counter modules to keep track of seconds. This way, you don't need to use up a cog keeping track of time...