-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 source= http://www.piclist.com/piclist/2004/02/08/175826a.txt? Olin Lathrop says: >6 - Wrote separate host program that used only the lowest level commands >to explicitly set Vdd, Vpp, PGC, and PGD directly from the host. There >was now at least one RS-232 command byte and a response byte between any >two transitions on any of the lines, in addition to specific longer >timeouts to make sure Vpp and Vdd stabalized. Verified all this on >scope. At this slow rate, signals now looked perfectly square on scope >(couldn't seen edges at all, only high and low levels). Could clearly see >time between clock and data edges on scope at 1mS/division setting. The "customer complaint" is in "read" and you have detailed an exhaustive "write" debug scenario. Following your step 6, I would display the device ID as it was read back. (verify original complaint) This should have been done initially, but it is a somewaht subtle point. Assuming failure, I would do the setup for the read device ID, then set up a program where I could toggle the clock line high or low, and read the return voltage as I clock out the ID from the target device. As a design question, why not do a turn-around on the data pin on the programmer, instead of having a voltage divider and a more complex circuit? - --- Aubrey McIntosh http://www.piclist.com/member/AM-vima-Y84 PIC/PICList FAQ: http://www.piclist.com -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 7.0.3 for non-commercial use iQA/AwUBQCe0kgKlSw8yssF7EQJEVQCgmxnhrXyPvEOJ8JucohQrug1+iY8AnRHk YY9/stx68ORyAsNfv8DKVH7r =QNDB -----END PGP SIGNATURE----- -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body