timer1 as counter

Log in or register to post comments
Go To Last Post
5 posts / 0 new
Author
Message
msd
msd's picture
Level: Wannabe
Joined: Thu. Nov 19, 2009
Posts: 84 View posts
#1
Posted by msd: Wed. Nov 24, 2010 - 05:55 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

In at90usb1287, I want to use timer1 as counter...
I have connected my pulse source to pin no.31 (T1)PD.6.

I want to use prescale=1
I have defined registers as

TCCR1A=0
TCCR1B=129(10000001)
TCCR1C=0

I am reading every 1 second the TCNT1 register...and then assigning to 0 after the read.
Its not working...
Are the value assigned registers correct?

Tags:

AVR Microcontrollers, megaAVR and tinyAVR
Top
Bronze Marktheusch
theusch's picture
Level: 10k+ Postman
Joined: Mon. Feb 19, 2001
Posts: 39995 View posts
Location: Wisconsin USA
Posted by theusch: Wed. Nov 24, 2010 - 06:20 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:

Its not working...

What does that mean?

Quote:

TCCR1B=129(10000001)

What does this say about how to set the CS bits for external clock?

Table 14-5. Clock Select Bit Description
CSn2 CSn1 CSn0 Description
0 0 0 No clock source. (Timer/Counter stopped)
001clkI/O/1 (No prescaling
010clkI/O/8 (From prescaler)
011clkI/O/64 (From prescaler)
100clkI/O/256 (From prescaler)
101clkI/O/1024 (From prescaler)
1 1 0 External clock source on Tn pin. Clock on falling edge
1 1 1 External clock source on Tn pin. Clock on rising edge

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

Top
msd
msd's picture
Level: Wannabe
Joined: Thu. Nov 19, 2009
Posts: 84 View posts
Posted by msd: Wed. Nov 24, 2010 - 06:56 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I want to use system clock 8Mhz...so its not prescaled....thats why it is 001. No prescaling.

Its not giving any counts, I have connected 100Hz pulse source..

Top
Phil.Barlow
Phil.Barlow's picture
Level: Hangaround
Joined: Sat. May 8, 2010
Posts: 154 View posts
Location: South Africa
Posted by Phil.Barlow: Wed. Nov 24, 2010 - 07:11 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
I have connected my pulse source to pin no.31 (T1)PD.6.
and
Quote:
I want to use system clock 8Mhz
.
These are two mutually exclusive things. You can count external pulses or system clock ticks. The bit settings posted by theusch above show how you choose one or the other.

Top
msd
msd's picture
Level: Wannabe
Joined: Thu. Nov 19, 2009
Posts: 84 View posts
Posted by msd: Wed. Nov 24, 2010 - 09:39 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

thanks for the info..I got the difference...its working after setting changed...

Top