Armed and ready with my new SX key and an assortment of chips, I am ready to enjoy my SX experience in all of its 75mhz glory!

Being new to the scene I am sure to have several "stupid" questions... Hey, I'm a pic guy. i need re-educating  :confused:  My first stupid question-


The 2k program space has me a tad concerned, I've generally worked with 8-14k pics.
How do folks work around that?  Can SX chips load external instructions from an eeprom?

There's really no way to execute from external memory directly. The SX doesn't present it's internal buses to the outside world. With an interpreter running on the SX then you can run from external code, but it will be a lot slower. The stamps are an example of that...

Eric,
Most of the time, worrying about too little code space before you start a project is like optimizing code before you finish writing the whole project - usually not necessary.  What kinds of projects are you thinking of doing?  If you have something that requires a ton of text, you may find a need for external memory to hold the strings.  Also, writing in assembly will stretch the 2K of memory quite far.  
Anyway, start working on a project and then see if you run out of memory.  If you do, post some specific questions here and I'm sure you'll find there are ways to save memory that you might not have thought of.

Eric,
 You could also use the SX48/52 Proto boards. The SX48/52 has 4K of code and about twice the RAM of the SX28.

 But you can do alot in 2K for example the SX-Video module uses only the SX28, okay big deal, BUT the character dot patterns are using 896 of the 2K program space. And except for the video generation code, it's written in SX/B.

Bean.

Eric,
have a look at this spec list for a DC motor controller:

- PWM-control three full H-bridge power drivers for DC motors
- Allow for reversing the motor's direction of rotation
- Receive commands, and send status information via I²C
- Monitor the status of reference and end-position sensors for all three motors
- Count tacho pulses generated by the motors, and stop them when the requested target position has been reached
- Check for over-current on the three motor supply lines
- Check for "blocked" conditions, i.e. a motor is supposed to turn but no tacho pulses are generated
- Check for "master-timeouts", i.e. no status information requested by the I²C master within a certain period of time
- Do a "soft start", i.e. slowly increase the motor PWM signal's duty cycle from 0% up to the requested value
- Drive an LED indicating the current status of the module
I could implement all these features using an SX28 with its program memory limited to 2 kWords, and the available RAM space. I still have some free memory left for more features. I must admit, this was the most challenging project I ever did with an SX28 but it turned out to work w/o problems. In the meantime, I could produce and sell more than 300 of these controllers to one of my customers.

I also have some PIC background (Atmel and other controllers as well) but I really like the SX because of its speed and flexibility. I'm pretty sure, you'll like it as well, so welcome to the club :-) .

After I posted I realized that it was indeed a stupid question since as Stephen mentioned the SX internal busses are not ported out.

Thanks for the replies - usually when I run out of space it is font sets / bitmaps for LCDs and things like that.

But can always use my 512K serial eeproms for that stuff.

http://forums.parallax.com/forums/default.aspx?f=7&m=85985

will answer your question, the die is static.

[Quoting: "Guenther Daubach"]Eric,
In the meantime, I could produce and sell more than 300 of these controllers to one of my customers.

[Quoting: "Paul Baker"]
http://forums.parallax.com/forums/default.aspx?f=7&m=85985

will answer your question, the die is static.

cbmeeks,
one unit sells for US$ 160.00 + S/H.