| ??? 09/28/04 21:41 Read: times |
#78335 - Correcting the SP89 schematic Responding to: ???'s previous message |
This question was asked here but I'm answering it in this thread to keep the topic in this thread.
Mr Craig what is wrong with the schematic in the homepage of SP89? http://www.xs4all.nl/~sbolt/e-ser89.html The problem was that there needed to be a 100 ohm resistor between MISO on the AT89S8252 and the PC parallel port. My current design has evolved a bit from the SP89 schematic but I presume a 100 ohm resistor on MISO would have been sufficient to make it work from the beginning. Interestingly I was in touch with the author of SP89 regarding the problem. He obviously swore that the program and hardware design worked. I can assure everyone that nothing I tried here without a 100 ohm resistor on MISO worked--but perhaps some parallel ports don't need it and that's why it worked for the author of SP89 and certainly many others that have used SP89. I'm surprised that they've never had to deal with this issue before, though. Regards, Craig Steiner |
