On Wed, 10 Dec 2008, Sebastian Kuzminsky wrote: > Date: Wed, 10 Dec 2008 14:34:59 -0700 > From: Sebastian Kuzminsky <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] Write error with hostmot2 and 7i43 board > > Peter C. Wallace wrote: >> With the 9805, I can see that the strobe ends in response to my wait signal, >> but the data is sampled somewhere around the falling (leading) edge of the >> strobe. I thought about an error caused by the port seeing /wait asserted too >> early so even tried putting a fair sized cap at the parallel port end of >> /wait, this slowed the handshake, but did not help reading tha data at the >> right time. Only way I could thnk of making the NetMos cards read right is by >> supplying read data when READ is high, but thats too ugly (bus conflicts etc) >> to consider seriously. > > I signed up for an account at MosChip.com, after that they let me see > their docs. Their FAQ for the 9805 says this: > > MosChip 9805 FAQ: >> An additional problem exists with EPP Mode. We have identified a timing >> problem >> in the chip that affects reading data from the remote device in EPP Mode. We >> are >> able to write data to the device (printer etc.) just fine under all >> conditions. The >> problem only affects reading data back from the device (scanner etc.) in EPP >> Mode. >> The symptoms result in the same Byte of data being returned for every read >> request. >> This problem does not affect ECP Mode. For this reason we recommend PS/2 or >> ECP Modes for applications that require bi-directional data transfers. > > > So yeah, the manufacturer admits that their hardware is broken, not much > anyone can do about that... Unfortunately. >
Crap, I have an account there. If I'd just bothered to read the FAQ I could have saved a lot of 'scope time! I must be getting too old for this. I just couldn't believe that they could have so basic an error in the most commonly available parallel port chip out there (15 FPGA configs trying to get it to work later...) At least I got really careful with the EPP timing in the latest firmware... > > -- > Sebastian Kuzminsky > One of my most productive days was throwing away 1000 lines of code. > -- Ken Thompson > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
