Reply by Tom Lucas September 20, 20072007-09-20
"Bruce" <tech@rentron.com> wrote in message 
news:A7WdnSYtiIePp2zbnZ2dnUVZ_gmdnZ2d@comcast.com...
> > "Tom Lucas" <news@REMOVE_tlcs_THIS_dot_TO_fsnet_REPLY_dot_co.uk> wrote > in message news:1189696690.5939.0@damia.uk.clara.net... >> 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? > > > 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.
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.
Reply by Bruce September 19, 20072007-09-19
"Tom Lucas" <news@REMOVE_tlcs_THIS_dot_TO_fsnet_REPLY_dot_co.uk> wrote in message news:1189696690.5939.0@damia.uk.clara.net...
> 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?
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 http://www.rentron.com
Reply by Tom Lucas September 13, 20072007-09-13
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?