View Full Version : Is my BS2sx fried?

08-12-2008, 07:43 AM
I picked up a BS2sx OEM bored at Defcon, but I can't get it to program. I'm using the Linux-based stampbc and a USB to Serial adapter.
I rigged up an LED to Vss (a 9V battery; with a 470 Ohm resistor) and RA1 on the stamp (which I believe is where the serial data comes in?) and could see it flash during the identification phase of programming, so I believe that the serial connection is working properly. (I've tested both with and without this LED.)

It's almost a certainty that while I was mucking around yesterday with less knowledge than I have today I conected 9V and/or 3.3V between various random combinations of the GPIO pins, Vdd, Vss, and Vin. I don't know how tolerant the stamp is of this sort of malicious behavior.

The BASIC Stamp IDE in Windows (through virtualBox) reports loopback but not echo on the board, and no device. Take this with a grain of salt, though, because sometimes VirtualBox is flaky with stuff like this.

So, then. Does anybody have any recommendations for further troubleshooting, or should I just order a new PIC?

Mike Green
08-12-2008, 08:48 AM
The BS2sx uses a custom programmed SX processor, not a PIC.· None of the stuff on the OEM board is very tolerant to having 9V randomly applied and 3.3V of varying polarity can also be destructive.· You may well have destroyed several things on the board.· It's generally a very bad idea to apply voltages above 5V to 5V logic and above 3.3V to 3.3V logic.· Sometimes· you can do this if you limit the applied current to a few mA with a series resistor.

Greg Loskorn
08-14-2008, 09:39 AM
Interesting. I just purchased 3 BS2sx OEM kits and the two that I have assembled do not work, I'll try the third one later. I've built many BS2 OEMs and they all work fine. I believe the BS2sx OEM is pin compatible with the BS2 OEM, so unplugging a working BS2 OEM and plugging in a BS2sx OEM should work fine, but it doesn't, I can't even get a valid stamp ID from the program (MacBS2). I've triple checked the two that I've built with no noticeable errors. I've got good voltage (5v) on Vdd of both the stamp chip and the memory chip, all polarity sensitive components are in correctly. Can't figure it out.

08-14-2008, 10:30 AM
I'd contact Parallax tech support if I were you.

- Stephen

Greg Loskorn
08-14-2008, 11:59 PM
According to Parallax tech support, all Stamps, except the BS2, have undergone firmware upgrades and require the Windows Stamp Editor v2.4. The current version of MacBS2 (v2.1b1) apparently won't work with anything other than the BS2. I've contacted the MacBS2 folks to see if they have plans to update. For now I must use the Windows editor (yuk). BTW, my BS2sx OEMs work great now with the Windows Editor. Oh well.

Mike Green
08-15-2008, 12:08 AM
MacBS2 is supposed to work with everything except the BS1 and the BS2px.
I've used it with a BS2p, BS2pe, and BS2sx without problems.

Chris Savage
08-15-2008, 02:44 AM

My guess is you don't have any BS2sx modules with V1.6 firmware on them. =)

Chris Savage
Parallax Tech Support

Mike Green
08-15-2008, 02:59 AM
I guess. Mine is a few years old. I don't have much reason to check the firmware version (if it ain't broke ... don't fix it).

Greg Loskorn
08-15-2008, 03:01 AM
Thanks for the info Chris. Can you give an approximate time for the v1.6 firmware upgrade? I'm in contact with MacBS2 and they are currently unaware of this issue.

Chris Savage
08-19-2008, 01:35 AM
My mistake…current firmware versions for our modules are as follows:

BS1: 1.4
BS2: 1.0
BS2e: 1.2
BS2sx: 1.3
BS2p: 1.7
BS2pe: 1.6
BS2px: 1.1

Chris Savage
Parallax Tech Support