Interrupt every 4 microseconds

AIVA · Joined: 15 Nov 2008 Posts: 18

Hi,

with the attached program I get interrupts every 16 microseconds but
I would like to have it every 4 microseconds

Thanks

$regfile = "m128def.dat"
$baud = 9600
$baud1 = 9600
$hwstack = 94
$swstack = 94
$framesize = 94
$crystal = 16000000
' Output
Ddre.6 = 1
'
Dim A1 As Byte
Led Alias Porte.6
'
Config Timer2 = Timer , Prescale = 1
On Timer2 Dec_timer
On Ovf0 Dec_timer
Enable Timer2
'
Enable Interrupts
'
Do
Loop
'
'
Dec_timer:
Toggle Led
Return

(BASCOM-AVR version : 2.0.7.8 , Latest : 2.0.8.6 )

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

you need to adjust the timer count value.
now it count to 255 and it flows over.
so preset it so it overflows earlier
when time is 16 us now, divide 256 by 4 is 64 times 3 makes 192

also set this value in the ISR after the toggle : tcnt2=192