How to generate 40MHz pulse with PWM command for my ultrasonic transmitter..please

[chenko]

cORRECTION....i want to use command PWM to generate 40KHz (NOT 40mHZ) pulse for my ultrasonic transmitter but i cannot find the way..I use Port E for the ultrasonic transmitter..I hope anyone can help me with code examples ... maybe suggest another way to generate that pulse... Thank you..

[skimask]

i want to use command PWM to generate 40MHz pulse for my ultrasonic transmitter bit i cannot find the way..I use Port E for the ultrasonic transmitter..I hope anyone can help me with code examples that may help me... maybe suggest another way to generate that pulse... Thank you..

40Mhz eh?
Probably 40Khz...
What have you tried so far? Can you blink an LED? If you can blink an LED, all you have to do is make it blink at 40khz and you're set.
What kind of hardware do you have?
What kind of software are you using?
What kind of programming have you done?
You don't give a lot of information to work with ya know.
There's a bunch of different ways to generate a 40khz pulse stream...Not a lot of ways to generate a 40Mhz pulse stream using a PIC.

[chenko]

I used PIC 16F877A in my project..My project is Smart System of Ultrasonic Car parking...The purpose of the project is try to detect the distance between car and obstacle then display the range on the LCD..I used PIC Basic Pro for the coding..I want to generate 40Khz (not 40Mhz like I state before) because that is my frequency of ultrasonic transmitter

[skimask]

I used PIC 16F877A in my project..My project is Smart System of Ultrasonic Car parking...The purpose of the project is try to detect the distance between car and obstacle then display the range on the LCD..I used PIC Basic Pro for the coding..I want to generate 40Mhz because that is my frequency of ultrasonic transmitter

Are you sure about that 40Mhz?
Are you sure 40Mhz falls in the range of an ultrasonic transmitter?

[chenko]

yup..you're correct...only 40kHz..i was mistaken by look to the other datasheet..thank you.. can you help me with the coding to generate that 40kHz..??

[mackrackit]

http://www.rentron.com/Infrared_Communication.htm

http://www.rentron.com/PicBasic/infr..._detection.htm