Section 12.8 of the PIC16F87x datasheet says: The Power-up Timer provides a fixed 72 ms nominal time-out on power-up only from the POR. The Power-up Timer operates on an internal RC oscillator. The chip is kept in RESET as long as the PWRT is active. The PWRT's time delay allows VDD to rise to an accept-able level. A configuration bit is provided to enable/dis-able the PWRT. The power-up time delay will vary from chip to chip due to VDD, temperature and process variation. See DC On power-up, the time-out sequence is as follows: The PWRT delay starts (if enabled) when a POR Reset occurs. Then OST starts counting 1024 oscillator cycles when PWRT ends (LP, XT, HS). When the OST ends, the device comes out of RESET. If MCLR is kept low long enough, the time-outs will expire. Bringing MCLR high will begin execution imme-diately. This is useful for testing purposes or to synchro-nize more than one PIC16F87X device operating in parallel Bob Ammerman RAm Systems. ----- Original Message ----- From: "wouter van ooijen & floortje hanneman" To: Sent: Monday, March 11, 2002 9:48 AM Subject: Re: [PIC]: In Circuit Programming - 16F877 > > The power up timer only runs on power up. The chip should start running > > almost immediately after MCLR is released. > > My idea too, but I can not find any data on how immediate. > > Wouter van Ooijen > -- > Van Ooijen Technische Informatica: http://www.voti.nl > Jal compiler, Wisp programmer, WLoader bootloader, PICs kopen > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body