by Dave Roberts [dave.roberts at BTINTERNET.COM]
I found that I could not raise TEST to Vihh ( 13 V ). If I did, it consumed excessive current.
This appeared as a low impedance resistive path to ground from TEST. Devices from different batches exhibited it.
I checked the datasheet, found internal inconsistencies and in the absence of other avenues, doubted the spec.
The answer was that voltage overshoot on the rising edge of TEST killed the chips. My designs use serial programming in the target hardware. Previous designs such as for the 14000 worked fine. This time wiring effects caused the overshoot. Specifically, the rising edge overshot by 3V for about 10 nsec - must use slower circuits in the future !
Also, for reference, the datasheet is in error in the following ways
Programing Datasheet DS30274B dated 1998
Main Device Datasheet DS30289A dated 1998
|file: /Techref/microchip/icsp17c766-dr.htm, 2KB, , updated: 2001/10/18 11:34, local time: 2021/10/25 06:19,
|©2021 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://www.piclist.com/techref/microchip/icsp17c766-dr.htm"> In Circuit Serial Programming the 17C766 </A>
|Did you find what you needed?|
PICList 2021 contributors:
o List host: MIT, Site host massmind.org, Top posters @20211025 Neil, Harold Hallikainen, Alan Pearce, RussellMc, Bob Blick, Allen Mulvey, Dwayne Reid, madscientistatlarge, Sean Breheny, Justin Richards,
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
Welcome to www.piclist.com!