how to calculate time(seconds) with 8051 timers????

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info_req

Joined: 20 Jun 2007
Posts: 44
Helped: 1

17 Jan 2008 8:02 8051 2 second timer

dear all,
i want to calculate time using 8051 timers, clock is 12MHz. i.e how to program timer for 1000000???

can i use timer0 and timer1, so that they count more than 16 bit????
thanks

microlab

Joined: 04 Mar 2006
Posts: 106
Helped: 3

17 Jan 2008 11:49 timers in 8051

Dear Friend

you can use any timers
but the maximum count you can get is only 65535+1
because the timer is a 16 bit timer
you can use other methods to get your required counts
but if you need exat timimg you should take care

ml

vsmGuy

Joined: 26 Jun 2006
Posts: 489
Helped: 28

17 Jan 2008 13:25 mcs51 use timer

use timer in a loop

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asoom

Joined: 28 Dec 2007
Posts: 247
Helped: 56
Location: jordan

17 Jan 2008 14:25 how to calculate 8051 timer

as mentioned, use two timers in loops. which means make a 65535 counts for the counter in the internal loop update the count for the timer in the external loop by 1. and so you'll achieve number of counts larger than 65535 (16 bits)..

Freddie Chopin

Joined: 08 Dec 2007
Posts: 103
Helped: 6
Location: Poland / Wroclaw

17 Jan 2008 15:52 how to calculate time in seconds

asoom wrote:

there is no need for 2 TIMERs to do that... how exactly are you going to increment a TIMER with ... a TIMER INT? you just need a timer and some variable to do the counting of interrupts.

0x41 0x56 0x45!!

aupa

Joined: 22 Feb 2007
Posts: 58
Helped: 1

17 Jan 2008 21:33 calculating time in 8051 interrupts

Hi!
in every timer0 interrupt, set the TH0 and TL0 to accurate frecuency and use a counter variable.

This variable is the auxiliar to use longer times than 16 bits

waseem

Joined: 13 Apr 2005
Posts: 241
Helped: 35

18 Jan 2008 7:05 calculate timer count

Hi!
You can do this very accurately by using just one timer.
See the complete keil project that is attached. Study the code carefully.
Ask if still not clear about the code.
Regards.

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