Re-Program SX basic stamp to use as an sx chip

thomasschubert

Hi

I have some old basic stamp sx 28 devices that I wont too use as a standard SX28. Is the fuse bit in the SX basic stamp burned. Is it possible to use my SX stamps as a normal SX28.

Mike Green

It should be possible to re-program a Stamp SX chip with another program. There have been a few cases over the years where some of the PBasic interpreters have been updated and Parallax will reprogram your SX chip with the updated interpreter. There is a fuse bit set that prevents you from reading the program in the SX, but that bit gets erased when you erase the SX in preparation for reprogramming it.

LoopyByteloose

On the BasicStamp, the SX28 chip is programed with a boot loader that transfers the tokens to the external EEPROM and an interpreter. While you can't read the code, you might just be able to completely overwrite it.

If you do what you are saying, the EEPROM would be useless unless you create support for it AND the PBasic interpreter would be removed along with the boot loader.

To do so, you would have to program the SX28 through the OSC1 and OSC2 with an SXKEY. All future programing would have to go through the OSC1 and OSC2 with an SXKEY.

All that is quite a bit of reconstruction of a device that is not particularly well suited for the conversion. Why not just buy some SX28 chips that are at clearance prices (about $1.25 USD each) now and use them without a huge salvage operation?

If you still want to go ahead, you can read the SX28 documentation to verify it can be overwritten. In any event, you are going to need to understand that document quite well if you are going to program from scratch.

thomasschubert

Hi

Thanks for the reply. Ive used the sx28 for over 10 years writing in assembler so the technical details are not a problem. I was just wondering if I could reuse the device as they are solder on a PCB and dident want to desolder the devices.
P.S Ive ordered 10 more.

thomasschubert

Hi

Thanks for the reply. Ive tried to identify the SX28 basic stamp device using an old SX-Key rev F, it gives a communications error. I also have a SX Blitz USB device but dont have the mini USB cable.
I have the 50MHZ resonator installed but read to read or program a device I dont have to remove it.

I wonder if the old rev F version of the SX key is giving the comm issue. Im using the latest version of SXB compiler.

Phil Pilgrim (PhiPi)

Theoretically, you should not have to remove the resonator. But in every SX-based board I've ever designed, I included a jumper that had to be removed before the SX Key could be plugged in. That jumper is what completed the resonator circuit. If you can remove the resonator without too much trouble, you might have better luck.

-Phil

RobotWorkshop

thomasschubert wrote: »

Hi

Thanks for the reply. Ive tried to identify the SX28 basic stamp device using an old SX-Key rev F, it gives a communications error. I also have a SX Blitz USB device but dont have the mini USB cable.
I have the 50MHZ resonator installed but read to read or program a device I dont have to remove it.

I wonder if the old rev F version of the SX key is giving the comm issue. Im using the latest version of SXB compiler.

I've done a lot of projects with the SX28 and SX48 over the years. I've found that if you want to use debugging or read the contents of an SX chip (Non protected) then it works best without a resonator in place. The only thing that I was able to do with the resonator in place was reprogram the SX chip. As long as you are just reprogramming it then you shouldn't have too much trouble. If it isn't working then I would ask to see a picture of your setup and how you are connecting your SX-Key to the chip. Is it right near the chip and are the connections solid?

Robert