Wade - I have had problems with Win98 and the p.port. Basically I send data from the PC to the PIC. However sometimes the data doesn't get through. I have spent quite a lot of time looking at this and have come to the conclusion that Win98 is the problem. My theory is that my peripheral does not implement some of the features that win98 and its deveice drivers require. I have come accross some literature that talks about windows querying the deveice on the lpt port and the device is supposed to send back data ( about its mode and plug'n'play config). My device does not do this and I think that it is because win98 keeps asking every now and then 'who are you and what are you doing hanging off my lpt port'. My logic behind this is that if I read my data register after each transfer ( so it should contain the data I just sent) a lot of the time this is not the case. I can send my data to the pic, the data is received because my device works, but by the time I read the data register it has something else in it. I can also see extra data strobes present during transmission. I am putting this down to win98, I could probably fix it by way of writing a virtual device driver but that is not an option right now. Anyway, pure MS-DOS is a great OS... If anyone else has any ideas..................on my problem.....thanks ----- Original Message ----- From: Wade Carpenter To: Sent: Thursday, August 02, 2001 1:44 AM Subject: Re: [EE]: PC Parallel Port -- Issues and Inquiry > Thanks to everyone fo the great response, it's much appreciated!! > > Darren - The host is a Win98 machine, and I'm just trying to use it > eventually for programming PIC's. The problem is, I started building up one > of these interface circuits, and the outputs I keep getting are not what I'd > expected. But I am just using a voltmeter to check this. I don't have a > scope at home. > > Olin - By the sound of your message, it seems that I am way off base here, > and that I won't be able to check this out without using a scope. So the > outputs of the parallel port are not a constant high or low then? I haven't > had a chance to read any of the links yet, nor try to implement any of the > suggestions. > > Thanks, > > Wade > > > ----- Original Message ----- > From: "Olin Lathrop" > To: > Sent: Wednesday, August 01, 2001 5:22 AM > Subject: Re: [EE]: PC Parallel Port -- Issues and Inquiry > > > > > Here's where I noticed that I'm not able to get it to work properly. I > > > tried to connect the port to a 74LS05 (Inverter) and the output and > inputs > > > to this chip are something like 1.3V. Total garbage. Regardless of the > > > port's state. I do believe that the software I'm using to toggle all of > > the > > > outputs on the port is correct. > > > > Something is definitely wrong electrically if the *outputs* of the 74LS04 > > are also around 1.3V. Check the power to the chip. What are the port > > output levels with nothing connected? Is the LS04 oscillating? You say > > your software to drive the port is working (although I don't know how you > > can tell given what you told us), so toggle all the bits in some pattern > and > > look at the bare outputs with nothing connected. If that looks fine, > > incrementally add more stuff and keep following the signals to see where > > they get lost. > > > > I like to use a counting pattern for this sort of thing. Each bit is a > > square wave with half the frequency of the next lower bit. This makes it > > easy to identify bits and detect shorts between them. > > > > > > ******************************************************************** > > Olin Lathrop, embedded systems consultant in Littleton Massachusetts > > (978) 742-9014, olin@embedinc.com, http://www.embedinc.com > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.