[SOLVED] i want a square waveform with f=7mhz by bascom avr

[hamid.abbaszadeh]

HI ALL
i want a square waveform with f=7mhz by bascom avr
plz help me
expecting your comments

 

[alexan_e]

There is no way to produce such high frequency even if your AVR runs at 20MHz

---------- Post added at 11:47 ---------- Previous post was at 11:44 ----------

Just to clarify things, I assume that by 7mhz you meant MHz (7000000Hz), is this correct?

 

[hamid.abbaszadeh]

hi alexan
i generat high frequence to 6mhz ,but thats minor than 7mhz
help me

 

[keith1200rs]

Sort out your mHz and MHz - it makes a difference of 1,000,000,000 times so affects the answer you will get.

Keith

 

[hamid.abbaszadeh]

7Mhz(7000000hz)

 

[alexan_e]

I would be very interested to see the way you have used to generate a frequency of 6MHz (as you said), I say it's impossible.

The max frequency you can get from a AVR pin is about 500KHz, the only exception is the SPI clock which can go up to CPU/4 but you can't have a constant square wave using it, you will have small pauses between each byte transmission.

Alex

 

[hamid.abbaszadeh]

now i generat 10Mhz with avr by ctc mode in timer1
setting:

Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: 14000.000 kHz
// Mode: CTC top=OCR1A
// OC1A output: Toggle
// OC1B output: Toggle
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer 1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=0x50;
TCCR1B=0x09;
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00

hope this clarifies

 

[alexan_e]

I stand corrected, yes CTC is another way that can be used for pulse generation.
Your code should be able to give an output very close to 7MHZ with a 14MHz crystal so what is the problem?

 

[hamid.abbaszadeh]

the problem solved