View Full Version : *SOLVED*Problems*SOLVED*

01-20-2007, 02:51 PM
I have been trying for awhile now to get my BS2 working with my computer. I can't seem to even get "Hello World" to work lol.... I got an extension serial cable because no one around here has a regular one, and took it apart and soldered it according to a diagram in a previous post. I get no loopback or echo when I go to identify. Any help would be great. I got the kit where you solder it together yourself and I know I did that correctly. I have a 9v battery connected to the Vin and Vss. Thanks

Post Edited (Asobu) : 1/21/2007 3:37:39 AM GMT

01-20-2007, 05:27 PM
IF your connections are all good, then I have to ask if your serial cable is too long. You said that it is an "extension" cable. DC voltages drop off proportionately with cable length. If the voltage dropped off enough to be outside spec, then the communication between your stamp 2 and pc will be lost. Try using a digital multimeter to check your connections. The Parallax cable is only 3 ft or so in length....

PJ Allen
01-20-2007, 09:30 PM
Sorry, but, an "extension cable" is exactly what you should be using (one with a male connector at one end and a female connector at the other): with pin 1 connected to pin 1, pin 2 to pin 2,... pin 9 to pin 9.· To me, this is a "regular one" and anything else is something else (something irregular.)·

Length, practically speaking, is not an issue here, as there is little current (and therefore little, if any,·"I2R loss.")

·1 <----------< 1
·2 <----------< 2
·3 <----------< 3
·4 <----------< 4
·5 <----------< 5
·6 <----------< 6
·7 <----------< 7
·8 <----------< 8
·9 <----------< 9

01-20-2007, 11:05 PM
If you modified your serial cables DB9 ends for the connections below then congratulations, for some reason you thought you needed a null modem cable which you don't.

I don't remember anything in the manual stating you needed a null modem cable nor anything different than a straight thru Serial extension cable. I have used up to 20 feet of extensions on my B-stamps without any problems and never had to modify any serial cable, Do it just like PJ Allen states and it should work.


Null modem connections, don't do the below with the B-stamps
DB9 #1 DB9 #2
3 - 2
2 - 3
7 - 8
8 - 7
5 - 5
6 - 4 this means pin 4 on DB9 #2 is connected to pins 1 and 6 on DB9 #1
1 - 4 this means pin 4 on DB9 #2 is connected to pins 1 and 6 on DB9 #1
4 - 1 this means pin 4 on DB9 #1 is connected to pins 1 and 6 on DB9 #2
4 - 6 this means pin 4 on DB9 #1 is connected to pins 1 and 6 on DB9 #2

01-21-2007, 02:11 AM
Well I soldered it back to how it was and now I get a loopback and an echo, but only when the battery is switched off http://forums.parallax.com/images/smilies/sad.gif. I still have the power set up like in my previous post. When I measure the Vdd and Vss I get exactly 4.98volts which tells me power is getting to it from the Vin pin and the voltage regulator is working correctly. When I use this simple code,

' Hello World
' This Program Prints the String "Hello World!"
' {$STAMP BS2}
' {$PBASIC 2.5}

' Variables

' Mainline

DEBUG "Hello World!", CR ' Print the string

END ' Stop Program

I get the error "No BASIC Stamps found." Is there something really obvious that I am doing wrong? Thanks for the help and prompt replies.

01-21-2007, 04:42 AM
Do you have all the pins in the cable tied through? You need more than rx, tx and ground. Sorry I don't remember which other pin you need and I'm too lazy to go look.

- Stephen

01-21-2007, 04:45 AM
I don't know if this is much of anything but when I go to the debug terminal and select the RTS the DSR lights up. When I select the DTR nothing happens. When I type in the top box the text show in the bottom box and the RX and TX lights flash each time I type. All of this happens when there is no power to the chip. I hope this helps some with my problem.

01-21-2007, 04:47 AM
I have it soldered back like PJ Allen shows

PJ Allen
01-21-2007, 04:57 AM
Asobu said...
I have it soldered back like PJ Allen shows
Have you verified that with an ohmmeter?··When in doubt, ohm it out.

Update --
DB9M (back)· 5 4 3 2 1···· DB9F (back)· 1 2 3 4 5
············· 9 8 7 6··················· 6 7 8 9

DB9M (Pins)· 1 2 3 4 5···· DB9F (sockets)· 5 4 3 2 1
············· 6 7 8 9······················ 9 8 7 6

Post Edited (PJ Allen) : 1/20/2007 10:04:00 PM GMT

01-21-2007, 05:16 AM
This is how that cable came wired (Attached).· Is this the cable that is needed? And I did "Ohm it out" to verify.

Post Edited (Asobu) : 1/20/2007 10:25:03 PM GMT

PJ Allen
01-21-2007, 06:15 AM
Your original post states that you are using a BS2.· Are you using the BS2 OEM kit?

01-21-2007, 06:38 AM
This is what I ordered and put together. http://www.parallax.com/detail.asp?product_id=27291 . I have verified all of the components to make sure the polarity is correct, if it has polarity, and that I had all of the correct components from the Bill of Materials. Do you know why the echo is "Yes" without power and "No" with in the Identifier? The loopback is always "Yes".

01-21-2007, 06:56 AM
Sigh. Yes, that IS a BS2 "OEM" kit. I'm hoping that you got the PIC chip from Parallax, because only the PIC chip from parallax is programmed with the parallax proprietary program that makes the OEM kit into a real BS2. An off-the-shelf PIC from Microchip won't work.

"Loopback" checks that the cable is plugged in, by checking a hard-wired loopback signal from pin 6 to pin 7 on the module. "Echo" checks that the transistor-based RS-232 circuit on the OEM is wired correctly. Only "Identify" actually 'talks' to the chip and expects an answer back from a properly powered chip.

If Echo is "Yes" without power, but "No" with power, I think it's highly likely you've mis-wired a transistor (installed it backwards, perhaps?).

01-21-2007, 07:01 AM
The PIC chip came with the kit... and I have checked the polarity of all of the components...

Post Edited (Asobu) : 1/21/2007 1:22:40 AM GMT

01-21-2007, 08:20 AM
I guess everyone gave up on me lol... I went to Radio Shack and found another serial cable, but it's still doing the same thing. So it must be something on the board or my serial port on the computer.

Post Edited (Asobu) : 1/21/2007 1:49:37 AM GMT

01-21-2007, 10:08 AM
LOL, you guys won't believe this... I'm such a newb. I was using the black spongy thing that the ICs came on to keep it off a metal surface. I guess that sponge thing would short the circuit and stop it from working correctly... I feel so stupid.

PJ Allen
01-21-2007, 08:19 PM
··· http://forums.parallax.com/images/smilies/rolleyes.gif

01-22-2007, 02:41 AM
Well, that's a new one. Yes, the 'black sponge' stuff is anti-static foam -- so yes, it is conductive. So you shouldn't use it in a circuit, it's only to protect the chip during shipping.

Good catch.

01-22-2007, 05:34 AM
Yeah, I had forgotten it was conductive...http://forums.parallax.com/images/smilies/blush.gif

Bruce Bates
01-22-2007, 12:38 PM
Asobu -

I'll tell you comething else that's interesting about it. It has a variable resistance when crushed or compressed. Place one lead of an ohmmeter on one long side, and the other probe on the other long side. Then squeeze the foam, and watch the resistance scale!

That essentially gives you a pressure to resistance transducer for FREE! FREE is GOOD http://forums.parallax.com/images/smilies/smile.gif


Bruce Bates

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01-23-2007, 03:13 AM
We did something very similar a long time ago in a class far far away. lol

We used a couple of sheets of aluminum foil separated by some anti-static foam and warped in soft plastic. It worked like charm but the resistance will change over time or if you press in exact same place over and over. But like Bruce said, "...for free! Free is good!"


There are 10 types of people in the world:

Those that understand binary and those that don't.