Post by thread:[PIC] 16F877A HV programming help

A silly question no doubt but... when programming the 877A does it need the xtal oscillator to be installed / operating or can I just clock the data in without it ? cheers, Mike W p.s. sorry if this has been duplicated -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.9.1 - Release Date: 4/1/05

Mike W wrote: > A silly question no doubt but... Well, um... > when programming the 877A does it need the xtal oscillator to be > installed / operating or can I just clock the data in without it ? If it needed the crystal oscillator running, how could you ever program in a circuit that used a different oscillator type? The requirements for getting into programming mode are clearly spelled out in the programming spec. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Mike W wrote : > A silly question no doubt but... > when programming the 877A does it need the xtal oscillator to be > installed / operating... No. How would those programmers where you just drop nothing but the PIC into a ZIF socket work if so ? Jan-Erik.

> when programming the 877A does it need the xtal oscillator to be > installed / operating or can I just clock the data in without it ? programming does not use the xtal/osc. note: in some borderline cases the actual osc mode which is programmed can have some adverse effect, but only when the programming algoithm/hardware is already bordeline. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

On Mon, Apr 04, 2005 at 12:19:25PM +0100, Mike W wrote: > A silly question no doubt but... Why would yhou think it was silly? > when programming the 877A does it need the xtal oscillator to be > installed / operating or can I just clock the data in without it ? No oscillator required. In fact if you have an oscillator installed you must ensure that that you don't get too many clocks in between the time that MCLR is in reset (0V) and the time that it reached programming mode (13V) BAJ > p.s. sorry if this has been duplicated No need to apologize. One of the purposes of this list is to ask questions. The answers are in the data sheets and the programming specifications though. BAJ

On Mon, 2005-04-04 at 07:54 -0400, Olin Lathrop wrote: > Mike W wrote: > > A silly question no doubt but... > > Well, um... It's actually not as silly a question as some may think. There are chips out there (other then PICs) that need a running oscillator to program. I believe the Atmel chips are some that require a clock running (be it a crystal, RC oscillator or something else). TTYL ----------------------------- Herbert's PIC Stuff: http://repatch.dyndns.org:8383/pic_stuff/

>> when programming the 877A does it need the xtal oscillator to be >> installed / operating or can I just clock the data in without it ? > > programming does not use the xtal/osc. Unlike AVRs in ISP mode which can be left dead-in-the-water by an inappropriate clock setting choice. RM

You can work fine with or without the crystal. All the data is clocked directly on the progrmaming pins (RB6/RB7) Robin Abbott Forest Electronic Developments 01590 681511 +44 1590 681511 (phone/fax) See our web pages : http://www.fored.co.uk {Original Message removed}

Yes, that is true with 8051 and AVR based micros! I was working with SP12 programmer for AVRs and by mistake I picked up a ceramic filter instead of a resonator (they look alike). I had hours of frustration with the programmer until I figured out that the chip was not oscillating when attempting to program it. -- Chetan Bhargava Web: http://www.bhargavaz.net Blog: http://microz.blogspot.com On Apr 4, 2005 7:37 AM, Herbert Graf <spam_OUTmailinglist2TakeThisOuTfarcite.net> wrote: > It's actually not as silly a question as some may think. > > There are chips out there (other then PICs) that need a running > oscillator to program. I believe the Atmel chips are some that require a > clock running (be it a crystal, RC oscillator or something else). TTYL