In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:

Kramer,

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 might 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 an extra, 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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