Basic Stamp 2 can not be identified
I had this strange thing happen yesterday.··I plugged in a board that I built using the Basic Stamp OEM Lite schematic that Chris·posted, and it worked for·about 10 seconds, then it·quit all together.····I built three other boards like this, and they all worked flawlessly.· The prop plug is communicating with the software, but it can not idenify any device.· I am receiving an echo on COM8, but it can not find a device type.· When I try to compile, it says "No Basic stamp found".· I checked for power on the BS2, and it showed 5Volts.· What else should I be checking?· How do I diagnose this problem?
Help would be greatly appreciated!!!!
Help would be greatly appreciated!!!!
Comments
Anything more requires a working, correctly powered BS2. Low batteries can cause this, as can missing/bad ground connections.
You sure the chip isn't in upside down?
···························· "Good" Board·· "Bad" Board
Pin #· Pin name·······
1········RTCC················ 0V················· 0V
2······· Vdd·················· 4.9V··············· 4.9V
3······· NC····················na·················· na
4······· Vss·················· 0···················· 0
5······· NC··················· na··················· na
6······· RA0·················· 2.7V··············· 266mV
7······· RA1·················· 1.2V··············· 1.4V
8······· RA2·················· 3V·················· 2.7V
9······· RA3··················· 4.9V···············2.4V
Pins 6-7 Go to the EPROM
Pins 8-9 go to the Prop Plug
10-25· These go to my buttons and knobs
26····· OSC2·················2.2V··············· 2.2V
27······OSC1················ 2.2V················2.2V
28····· MCLR················ 4.9V················ 0.6V
Based on this data, I suspect pins 6 (connects to DATA on the EPROM), pin 9 (connects to the diode, then to the Prop-Plug), and pin 28 (connects to MCLR.··· The OEM sematic is posted here:· It is in the completed projects forum.
http://forums.parallax.com/showthread.php?p=567989
I am at a loss about what do check for next.· Thanks!
·
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Chris Savage
Parallax Tech Support
I left out the brown-out detector.· It was not included.· I could not find anything wrong with the wiring.· I am still at a loss. I may just throw out the board and start from scratch.
I mounted the prop-plug directly on top of the PCB board.· I had to remove the plastic Prop-Plug label in order to get it to sit flush and low profile.··· I am thinking I may have caused a short on the Prop-Plug by mounting it directly on the board.· I will place some insulation under the Prop-Plug and see how that works out.
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Chris Savage
Parallax Tech Support
It seems as if the order in which you power up the board, plug in the USB, and compile the code is very important.· It has to be done in this order:
1) Open the Basic Stamp software
2) Power up the PCB board
3) Plug in the USB cable
4) Press Play to upload your code to the Stamp
If the debug screen is all ready open when you plug in the USB, the Stamp will not be identified.
If your board is not powered up when you first plug in the USB, then the Stamp will not be identified.
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This quirky behavior occurs for both the Prop Plug and the USB2SER.
Can anyone explain why it is so finicky?· I was racking my brains trying to figure out what was wrong for days!
Eric
USB is a very nice, and very flexible standard. However, you DO have to have a USB 'master' (your PC) and a USB 'slave' (your board).
USB was designed to be 'hot pluggable'. When you first plug in a USB device, there's an "identify" cycle the USB hardware/software goes through. This lets the "master" load the correct driver code into the 'master' for the 'slave' hardware, so the "master" can communicate properly with the 'slave'.
The result of all of this is that the USB "Serial Port" that your BS2 board uses doesn't "exist" at all on your PC, until AFTER you plug in your fully powered USB connection. So, if you bring up the IDE and Debug screen first, it doesn't find that "serial port", and doesn't know to use it.
I would assume you could plug in the fully powered USB connection BEFORE you brought up the IDE, though.
If the BASIC Stamp starts sending data (using DEBUG or SEROUT) through the port before the USB cable is connected, the PC may see the device as a mouse. This is why we recommend having our development boards powered off when connecting the USB cable. When it is detected as a mouse the BASIC Stamp Editor cannot see it, and in some cases it can affect your normal mouse movement.
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Chris Savage
Parallax Tech Support