Specialized counters

inaki · 2006-04-12 18:03

Where is explained the use of these 'two specialized counters' that I keep hearing about ?
I was puzzled reading some of the code·writen around·those counters.

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pjv · 2006-04-12 18:17

Hi Inaki;

I have not searched the field, but I'm not sure if much pulblic information exists about those or the video peripheral. I believe Parallax is writing that stuff up during this period prior to formal release.

Cheers,

Peter (pjv)

Jon Williams · 2006-04-12 18:37

In order to get some information out, Chip wrote a documented demo; there's a lot left to do, but this should get you started.· Note that this file needs to be opened with a Unicode-compatible viewer using the Parallax·font.

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Jon Williams
Applications Engineer, Parallax

Gadgetman · 2006-04-12 19:26

Where's the Parallax font?

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Don't visit my new website...

inaki · 2006-04-12 19:37

Thanks Jon.

Wow! I think I need time to assimilate this information. Anyway, now·I understand why these are called 'specialized counters' although 'counters' is a little humble name for such powerful registers.

I see this subject has a lot of possibilities.·I can even foresee·a book: 'Recipes for·exploiting·Propeller's specialized counters".

Well at least I expect an article on N&V dedicated to this subject ! ;-)

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Jon Williams · 2006-04-12 19:40

I attached the Parallax font to a sticky thread in this forum: http://forums.parallax.com/showthread.php?p=581530

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Jon Williams
Applications Engineer, Parallax

Jon Williams · 2006-04-12 19:41

Yes, once I get a better grasp on the counters I will do an N&V project -- probably my Servo16 object which is a virtual version of our PSC that runs in its own cog.

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Jon Williams
Applications Engineer, Parallax

Direct Digital Labs · 2006-07-30 00:56

I've been playing with the·Counters in a Cog and was having trouble coming up with a simple way to have Counter A change State of “Pin 0” every time the System Counter increments by 12 and Counter B change in increments of 768. I can do Multiples of Two without any·problems; it's multiples of 3 that seem to be difficult.
·
I was able to get the correct clock frequencies out of the code posted above, but,·there was a very small error·so the two clock pulses were not in perfect sync.
·
In my application Pin 1·needs to be exactly·1/64 of Pin 0. ·I can work out timing to sync the two clocks.
·
Maybe I'm completely·unable to grasp the concept. Maybe·someone could help shed some light on these wonderful counters·since little documentation is currently available for them, that I can find.
·
Here is the code I’ve been using to test the counters.· Currently it is set to output 40MHz on pins 0 and·1.

CON _clkmode = xtal1 + pll16x
_xinfreq = 5_000_000
PUB Start
cognew(@Output, 0)                                      'Launch Code
DAT
'-------------------------------------------------------------------------------- 
Output        org       0                               'Begin at Cog RAM addr 0
              mov       dira, Pins                      'Set All Pins to output
              
              mov       ctra,CTRA_MODE                  'Setup CTRA
              mov       frqa,FREQA
              mov       phsa,PhaseA
              
              mov       ctrb,CTRB_MODE                  'Setup CTRB
              mov       frqb,FREQB
              mov       phsb,PhaseB 

:loop
              {main code here}
              jmp       #:loop
Pins          long      $FFFFFFFF                       'All Pins Output
CTRA_MODE     long      $10000001                       'NCO Single Ended Output Pin 0 ($0B800000 PLL x16 /128 SEO)
CTRB_MODE     long      $10000001                       'NCO Single Ended Output Pin 1
FREQA         long      $80000000                       '40 MHz
FREQB         long      $80000000                       '40 MHz
PhaseA        res       1
PhaseB        res       1

-Dan

Post Edited (Direct Digital Labs) : 7/31/2006 3:09:12 PM GMT

Specialized counters

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