© MCS Electronics, 1995-2007

‘Now use PING at the command line to send a ping:

PING 192.168.0.8

Or use the easytcp application to ping the chip.

CONFIG TIMER0

Action

Configure TIMER0.

Syntax

CONFIG TIMER0 = COUNTER , PRESCALE= 1|8|64|256|1024 ,

EDGE=RISING/FALLING , CLEAR TIMER = 1|0

CONFIG TIMER0 = TIMER , PRESCALE= 1|8|64|256|1024

Remarks

TIMER0 is a 8 bit counter. See the hardware description of TIMER0.

When configured as a COUNTER:

Note that some new AVR chips have different prescale values. You can use these.

Notice that the Help was written with the AT90S2313 and AT90S8515 timers in mind.

When you use the CONFIG TIMER0 statement, the mode is stored by the compiler and the TCCRO register is set.

When you use the STOP TIMER0 statement, the TIMER is stopped.

When you use the START TIMER0 statement, the TIMER TCCR0 register is loaded with the last value that was configured with the CONFIG TIMER0 statement.

So before using the START and STOP TIMER0 statements, use the CONFIG statement first.

Example

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'First you must configure the timer to operate as a counter or as a timer 'Lets configure it as a COUNTER now

'You must also specify if it will count on a rising or falling edge

Config Timer0 = Counter , Edge = Rising 'Config Timer0 = Counter , Edge = falling

'unremark the line aboven to use timer0 to count on falling edge

'To get/set the value from the timer access the timer/counter register 'lets reset it to 0

Tcnt0 = 0

Do

Print Tcnt0

Loop Until Tcnt0 >= 10

'when 10 pulses are count the loop is exited 'or use the special variable TIMER0

Timer0 = 0

'Now configire it as a TIMER

'The TIMER can have the systemclock as an input or the systemclock divided 'by 8,64,256 or 1024

'The prescale parameter excepts 1,8,64,256 or 1024

Config Timer0 = Timer , Prescale = 1

'The TIMER is started now automaticly

'You can STOP the timer with the following statement :

Stop Timer0

'Now the timer is stopped

'To START it again in the last configured mode, use :

Start Timer0

'Again you can access the value with the tcnt0 register

Print Tcnt0 'or

Print Timer0

'when the timer overflows, a flag named TOV0 in register TIFR is set 'You can use this to execute an ISR

'To reset the flag manual in non ISR mode you must write a 1 to the bit position

'in TIFR:

Set Tifr.1

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The TIMER1 also has two compare registers A and B

When the timer value matches a compare register, an action can be performed

COMPARE A The action can be:

SET will set the OC1X pin

CLEAR will clear the OC1X pin

TOGGLE will toggle the OC1X pin

DISCONNECT will disconnect the TIMER from output pin OC1X

And the TIMER can be used in PWM mode.

You have the choice between 8, 9 or 10 bit PWM mode

Also you can specify if the counter must count UP or down after a match to the compare registers

Note that there are two compare registers A and B

COMPARE A PWM PWM compare mode. Can be CLEAR UP or CLEARDOWN

Using COMPARE A, COMPARE B, COMPARE A PWM or COMPARE B PWM will set the corresponding pin for output. When this is not wanted you can use the alternative NO_OUTPUT version that will not alter the output pin.

For example : COMPARE A NO_OUTPUT , COMPARE A PWM NO_OUTPUT

Example

'-----------------------------------------------------------------------------

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Dim W As Word

'The TIMER1 is a versatile 16 bit TIMER. 'This example shows how to configure the TIMER

'First like TIMER0 , it can be set to act as a TIMER or COUNTER 'Lets configute it as a TIMER that means that it will count and that 'the input is provided by the internal clock.

'The internal clock can be divided by 1,8,64,256 or 1024

Config Timer1 = Timer , Prescale = 1024

'You can read or write to the timer with the COUNTER1 or TIMER1 variable W = Timer1

Timer1 = W

'To use it as a COUNTER, you can choose on which edge it is trigereed Config Timer1 = Counter , Edge = Falling , Prescale = 1

'Config Timer1 = Counter , Edge = Rising

'Also you can choose to capture the TIMER registers to the INPUT CAPTURE registers

'With the CAPTURE EDGE = , you can specify to capture on the falling or rising edge of

'pin ICP

Config Timer1 = Counter , Edge = Falling , Capture Edge = Falling , Prescale = 1024

'Config Timer1 = Counter , Edge = Falling , Capture Edge = Rising

'To allow noise canceling you can also provide :

Config Timer1 = Counter , Edge = Falling , Capture Edge = Falling , Noise Cancel = 1 , Prescale = 1

'to read the input capture register : W = Capture1

'to write to the capture register :

Capture1 = W

'The TIMER also has two compare registers A and B

'When the timer value matches a compare register, an action can be performed Config Timer1 = Counter , Edge = Falling , Compare A = Set , Compare B =

Toggle , , Clear Timer = 1 'SET , will set the OC1X pin

'CLEAR, will clear the OC1X pin 'TOGGLE, will toggle the OC1X pin

'DISCONNECT, will disconnect the TIMER from output pin OC1X 'CLEAR TIMER will clear the timer on a compare A match

'To read write the compare registers, you can use the COMPARE1A and COMPARE1B variables

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