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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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--- pics with gate control of internal timer clock counting- |
Posted: Sun Oct 23, 2011 6:07 pm |
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I inherited a design with a 16f887 using the T1 gate function to get 2 us resolution for event time events using a sys clock of 16 mhz.
I'd like to improve the resolution to 1 us with an 18F part at 32 mhz , but find that this gating feature is not universally available.
(because of processing time requirements I can't simply jump the present prescalar setup down from /8 to /4 - as that already failed )
A search of the forum was not successful -
the microchip com web site 'java' interactive device selector was no help either.
Can anybody point me to a resource that clearly identifies parts WITH the
T1 ( or really ANY of the timers ) WITH the external gate feature ?? |
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PCM programmer
Joined: 06 Sep 2003 Posts: 21708
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Posted: Sun Oct 23, 2011 7:01 pm |
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One way would be to use Google. Search the Microchip website for the
following things: A PDF file for 18F with a T1G pin. Put in the TBLRD
instruction to make sure it doesn't return 16F or 12F results:
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site:microchip.com type:pdf PIC18F T1G TBLRD |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Mon Oct 24, 2011 6:39 pm |
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i could not make ANY web or microchip search turn up a result ;-((
i only asked here - in case somebody knew offhand -
of any 18F , 5V parts that had T1G support
so i stated a microchip support ticket on it.
will share the results when i hear from m-chip on this question
A-B |
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temtronic
Joined: 01 Jul 2010 Posts: 9174 Location: Greensville,Ontario
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Posted: Mon Oct 24, 2011 6:53 pm |
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Any chance you could use another pin as the 'T1G' pin to control the timer on/off bit in the SFR ?
Just trying to think of options..... |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Mon Oct 24, 2011 7:23 pm |
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I also searched the collection of PDF's on the dozen 28 & 40 pin 18f's i've evaluated or used in a design. No luck there either - will wait and see what m-chip says. |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19369
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Posted: Tue Oct 25, 2011 2:11 am |
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Did you actually 'try' PCM Programmers suggestion?.
It merrily returns 9 PIC18 chip data sheets, with the requirements. The very first one, 64MHz operation, gate control. The F version as opposed to the LF, runs to 5.5v max.
A good demo of how to actually _use_ Google....
Best Wishes |
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temtronic
Joined: 01 Jul 2010 Posts: 9174 Location: Greensville,Ontario
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Posted: Tue Oct 25, 2011 5:33 am |
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It is amazing that Google can find the 'right stuff' FAST ! Now , if it'd show me WHERE I left my truck keys.......I'd be outta here ! |
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