SX-Blitz Overheating
John Couture
Posts: 370
Again putting problem here before bothering tech support.
SX-Blitz
1) When I plug it into the desktop, it blinks and registers properly (i.e. COM5) on the Device Manager
2) I fire up SX IDE and it shows COM5, so I select it.· I then load a simple program in (i.e. Blink1.sxb)
3) I then·plug the Blitz into a good PDB (i.e. #8002),·and power the PDB on.· After about 13 seconds, the SX-Blitz gets very hot and when I press PROGRAM it reports that COM5·cannot be found.
4) SX-Blitz does not heat up when only connected to the live USB cable.
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John J. Couture
San Diego Miramar College
SX-Blitz
1) When I plug it into the desktop, it blinks and registers properly (i.e. COM5) on the Device Manager
2) I fire up SX IDE and it shows COM5, so I select it.· I then load a simple program in (i.e. Blink1.sxb)
3) I then·plug the Blitz into a good PDB (i.e. #8002),·and power the PDB on.· After about 13 seconds, the SX-Blitz gets very hot and when I press PROGRAM it reports that COM5·cannot be found.
4) SX-Blitz does not heat up when only connected to the live USB cable.
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John J. Couture
San Diego Miramar College
Comments
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
sorry, this is not correct - the SX-Blitz does not have an on-board clock generator. In most cases, a resonator or crystal attached to the SX OSC1 and OSC2 pins may be in place while the device is programmed by the SX-Blitz. This is also true for the SX-Key as long as you use it for programming only but debugging only works with the clock device removed, or at least disconnected from the OSC1 pin. When using an external clock generator with its output attached to the OSC1 pin, it must be removed before programming and/or debugging in most cases, as it adds too much load, and may be damaged by the 12V programming voltage fed into the OSC1 pin by the SX-Blitz/Key.
John,
The SX-Blitz USB is actually powered from two sides: The on-board FT232R USB-serial adapter chip is powered from the USB port, where the on-board SX20 is powered from the target device. IOW - as long as you only connect the SX-Blitz to the USB port, the FT232R gets power, and is detected by the virtual com port driver, and Windows makes available a new COM port (COM 5 in your case), and the IDE can detect it.
When the SX-Blitz gets hot while connected to the target system (I assume it is the SX20 that gets hot in this case) unfortunately indicates that the poor SX20 is fried. When you press PROGRAM, the SX-Key IDE tries to establish a communication link to the SX-Blitz which fails because the SX20 does not answer. This is why the IDE reports COM5 can't be found, or does the message actually say "SX-Blitz not found on COM5"?
I'm sorry for giving you such bad news but it seems to me that something severe happened which fried the SX28 you were using on the PDB, but also the SX-Blitz.
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Greetings from Germany,
G
I happen to only have the SX-Key and presumed that this was a standard operation for both. I tried to confirm my advice from the Parallax posted documents and find that the somewhat lengthy SX-Key Manual is suppose to cover both the SX-Blitz and SX-Key. It has no seperate notes for the SX-Blitz. Page 13 shows a schematic of the SX-Key without a resonator or crystal.· That is misleading.
It seems to me that a one page Quick Start/Trouble Shooting document for each device would be most helpful but is missing. It is not that I expect you to write such. With your support, staff at Parallax may better resolve the presentation problems and resulting confusion. [noparse][[/noparse]They generally provide such material with every new hardware item.]
From time to time, we have had a lot of redundant discussion of overheating SX-Keys and the SX-Blitz. In particular, new users seem more hazard prone and to fear the worst, so a short and focused document seems best.
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
Post Edited (Kramer) : 2/9/2008 12:42:30 PM GMT
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
on both, the SX-Key and the SX-Blitz, the OSC1 and OSC2 pins are connected to the on-board SX20 via series resistors. Although a solder bridge on the target system would prevent the SX-Key/Blitz from normal operation, it is very unlikely that such a solder bridge could frie the SX20, or cause it to produce abnormal heat as the resistors limit the maximum current.
Causes for frying the on-board SX20 could be:
- Wrong orientation. Normally, it does not harm the SX-Key/Blitz when you plug it onto the 4-pin header reversed by 180° (it simply does not work then) but attaching it with an offset, e.g. three pins connected, and one pin floating will be lethal to the SX-Key/Blitz in most cases.
- Excessive electro-static discharge. Let's assume, the SX-Key/Blitz is connected to a PC (no matter if to a COM port, or to a USB port), the PC's ground, and Vss on the SX-Key/Blitz are tied together. When you now connect the SX-Key/Blitz to the target system, any static load of the target will be discharged through the pin that connects first. When this is the OSC1 pin, for example, you could be in bad shape. Therefore, it might be a good idea to tie together the PC ground, and the Vss potential on the target system by a separate wire.
I agree with you that a short Start/Trouble Shooting document for each device would be very helpful. As a matter of fact, it is most likely that I'm going to write them soon
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Greetings from Germany,
Günther
I've done the 180 degrees insertion several times and had the uneasy feeling of being lucky that nothing died. It certainly is nice to know that doesn't usually damage anything. These days, I always check the documentation before proceeding as some of my boards are homemade.
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PLEASE CONSIDER the following:
Do you want a quickly operational black box solution or the knowledge included therein?······
We did find that on one of the boards the SX28 was bad and that was replaced. I guess what I need to do is to review with everyone proper orientation with the key and next time I offer the class, I will install the SX28 in the PDB myself (grin).
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John J. Couture
San Diego Miramar College