Microchip PicKit Serial Analyzer Crash

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- Tom Lucas
  
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posted
16 years ago

Thu, Sep 13, 2007 3:19 PM

I'm using Microchip's PicKit serial analyzer to find out why my I2C is playing up. The analyzer is set up to be an I2C slave and to accept external power. However, when I start communication then the PC software crashes and the Just-In-Time debugging reports a System.NullReferenceException error.

I've downloaded the latest version of the software, updated the firmware in the analyzer and installed the latest service pack for Visual Studio .net 2003. Perhaps I need a later version?

Anyone come across this sort of thing before?

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- Bruce
  
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posted
16 years ago

Wed, Sep 19, 2007 5:04 PM

I haven't used the PicKit serial analyzer, but if it's causing a system crash on your PC, I would definitely submit a support ticket at Microchip.com.

Regards,

-Bruce

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- Tom Lucas
  
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posted
16 years ago

Thu, Sep 20, 2007 8:19 AM

I've been considering it, but apparently there is a fair wait on answers and I'm not sure I can be bothered. It's only a cheap bit of kit so it is probably not worth my time messing about with it.

It turned out that the I2C problem I thought I had was actually device related. It seems that the NXP PCF8574 bus expander is not the same as the TI PCF8574 even though they are supposed to be identical on paper. For no obvious reason the NXP device, in slave mode, pulls the SDA line down to half way while a stop and start bit are transmitted to it. The TI device doesn't do this and works fine.

This is not the first time we've seen this with NXP devices. We had a bog standard 244 buffer and the NXP part would only drive the bus half way. Replaced it with a fairchild part and had no problems.