Is my bs2sx dead?
I have an oem bs2sx board.· Unfourtunately, it can't be identified by my computer (I am using a regular serial connection
).· What I have noticed is that with the power applied, Loopback and echo fields are marked as "yes" while with the power off only loopback is marked as "yes". The version and device fields are empty.· This occurs whether or not the interpreter chip is inserted.
Is there a test that can be performed to check if the chip is dead? I have already verified that 5 volts are fed to it, but other than that, what can be done?
Thanks for the help,
Frank
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).· What I have noticed is that with the power applied, Loopback and echo fields are marked as "yes" while with the power off only loopback is marked as "yes". The version and device fields are empty.· This occurs whether or not the interpreter chip is inserted.
Is there a test that can be performed to check if the chip is dead? I have already verified that 5 volts are fed to it, but other than that, what can be done?
Thanks for the help,
Frank
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Comments
·· What version of the BASIC Stamp Editor are you using?· If it's not 2.2.6 then please download the latest version from our website at the following link and try that.
http://www.parallax.com/html_pages/downloads/software/software_basic_stamp.asp
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Any other insights?
Thanks,
Frank
This is a very common startup problem as Windows and various firewall programs are less and less willing to provide automatic access to any port on a computer.
Is your BS2sx dead? Highly unlikely unless you gave it a nice jolt of raw power.
I just had my BS2p hooked up wrongly [noparse][[/noparse]no ground, the VSS was connected to RESET by error] and it seems to be just fine.
Reverse polarity and significant overvoltage are the great destroyers on the power supply side.
On the I/0, they can both do damage as well AND you have to limit the current to about 20ma. When in doubt, use a 220 ohm protective resistor on PINs 0-15.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Is it possible that the pinout of the bs2sx interpreter has changed since 2004 (when the board was purchased) causing this mal function?
·
No, the pinouts have not changed at all on the BS-2SX interpreter, to my knowledge.
Has this BS-2SX OEM set-up ever worked, or is this first time you've tried to use it?
Are you using a "straight through" (pin 1 to pin 1, etc) serial cable?
Is this a desktop computer, or a laptop? Which operating system are you using?
Are you using batteries for power, or an AC power adapter?
Regards,
Bruce Bates
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-This is the first time I have tried to use it (never worked before).
-Cable is straight through.
-Tried on both my laptop (win xp pro) and desktop (win xp home) with same results.
-Tried batteries (9 V)·and AC supply (7.5 V, 60mA) --- Power was my first concern: I·measured 5.01 volts between Vdd and Vss directly on pins of the chip with·battery and 4.79 with adapter.
Thanks for the reply,
Frank
I still suspect there is an interface problem unless the chip was either assembled wrongly [noparse][[/noparse]can that be possible with an OEM chip?] or it is damaged 2nd hand goods.
The interface of the serial port to the usual BasicStamp requires two small capacitors involved with the DTR line, nothing on the Rx or Tx. Those are on the OEM board under the 3 transistors.
Also, you might have the transistors either wrongly positioned. [noparse][[/noparse]I get dyslexic when I look at a transistor].
Can you turn off echo and loopback? Do you have pins 6 and 7 on the RS-232 DB-9 connected? I believe that is a requirement to tell the computer that a BasicStamp is plugged in.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Post Edited (Kramer) : 8/14/2006 12:32:30 PM GMT
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Pins 6 and 7 are indeed connected, caps are in for DTR, RX and TX are·floating and the transistors are correctly positioned (incidently, couldn't transistor manufacturers put a dot on the casing next to the emmiter pin; I always need to double check with transistors to make sure they are positioned correctly!).
Loopback is·on when the board is connected and off otherwise.· Echo is on when the power is applied to the board.· This confirms RS-232·comm is ok.·
I know the port on the computer side is functionning properly·because·I·can communicate·with my TI graphic calc.
I have been checking all soldering joints, confirming connections with the OEM circuit diagram but still no positive results.·
Thanks to all for the good info!·
Frank
·· You didn't reply about the power supply...Is it AC or DC output?
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Chris Savage
Parallax Tech Support
csavage@parallax.com
The output of the·power supply·is a 7.5 Volt DC supply.· Could it be a problem that it has a max rating of 60 mA?· If so, could insufficient current have damaged·it?· The chip·was·ordered from a local distributor, but is still a·genuine parallax part.· I am still waiting for a response from them concerning my problem.· However, I was·optimistic about finding a solution other than a "dead chip".
I·truely appreciate·this forum's·concern and help,
Frank
I imagne that you would merely cause a voltage drop that would make the BS not operate, but damage needs excessive energy applied at a weak point. Seems you don't have that condition.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
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Chris Savage
Parallax Tech Support
csavage@parallax.com
If you are building your own PCB then that opens up a whole bunch of other questions. I've done it on a protoboard using the individual OEM components and as long as you follow the schematic it works well.
Good luck,
Robert
Thanks for all the help,
Frank
·
·· That makes a difference...I thought you had a BS2-OEM and had recently replaced the interpreter on it.· You have a home-brew OEM unit though...
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Chris Savage
Parallax Tech Support
csavage@parallax.com