Post by thread:[PIC]: How to disable one of two identical 16F877s

Hi All. Is it possible to take two identical pics (e.g. PIC16F877), wire them together, pin-to-pin for all but some particular pins, and disable (hi-Z) one entire chip such that it does not affect the other? My intended application is to have a soldered-in TQFP PIC16F877, and also a PLCC socket for the same chip (same model, different package, of course). I'd like to be able to "disable" the soldered-in part (perhaps via a DIPswitch) and put an MPLAB-ICE emulator probe into the socket. When I'm done debugging, I remove the emulator probe, "enable" the soldered-in part, program it via ICSP, and voila I'm done. Is is as simple as holding the soldered-in chip in RESET via -MCLR, while the probe is in the socket? Thanks, -- ______________________________________ Andrew E. Kalman, Ph.D. spam_OUTaekTakeThisOuTpumpkininc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

>Why not just use the ICD capability of the 877? Because it can't trace. -- ______________________________________ Andrew E. Kalman, Ph.D. aekKILLspampumpkininc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body

On Tue, 21 Nov 2000 15:36:19 -0700, you wrote: >Hi All. > >Is it possible to take two identical pics (e.g. PIC16F877), wire them >together, pin-to-pin for all but some particular pins, and disable >(hi-Z) one entire chip such that it does not affect the other? > >My intended application is to have a soldered-in TQFP PIC16F877, and >also a PLCC socket for the same chip (same model, different package, >of course). I'd like to be able to "disable" the soldered-in part >(perhaps via a DIPswitch) and put an MPLAB-ICE emulator probe into >the socket. When I'm done debugging, I remove the emulator probe, >"enable" the soldered-in part, program it via ICSP, and voila I'm >done. > >Is is as simple as holding the soldered-in chip in RESET via -MCLR, >while the probe is in the socket? This ought to work - all I/O's will tri-state in reset. Not sure about the oscillator though - I think this normally runs during reset so you may need a link to break OSCOUT as well. -- http://www.piclist.com hint: To leave the PICList EraseMEpiclist-unsubscribe-requestspam_OUTTakeThisOuTmitvma.mit.edu

On Tue, 21 Nov 2000 19:15:05 -0700, you wrote: >>Why not just use the ICD capability of the 877? > >Because it can't trace. And it's slow as hell compared to a proper ICE And it can't do trigger-out, or break on register contents, etc. etc..... -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestspam_OUTmitvma.mit.edu