ESP8266 Community Forum

Dakota wrote:Thanks a lot. Any help wil be great.
This is my code right know.

https://pastebin.com/Yi2UepfX

The original program is for arduino ... I just change it a bit

try to use OS_TIMER_US, i tested and works! find in google how to active OS_TIMER_US, because is default "disable".. if you can't do this, tell me. i help you![/quote][/quote]


you can use 25MHz crystal with special pin function! (if you need). see GPIO FUNCTIONS in google.. i see an tutorial in PORTUGUESE teaching use OS_TIMER_US, go to end of tutorial and see, i try and work.
http://portal.vidadesilicio.com.br/soft ... o-esp8266/

no, crystal frequency IS NOT 80MHz.
take a look and see: 26MHz

so what is the 80MHz? --> the cpu clock

how do you get 80MHz from 26MHz ??? not really a multiple --> PLL (cheap) so you will have phase jitter

What quality does the crystal have ??? probably low +/- --> ???ppm --> so the 80MHz will be ???

Temperature stability will be ???

As I wrote, your generated frequency needs to be within a window of several 10Hz +/- around the 77500Hz
stable for at least 2 minutes for the clock to detect one correct packet (usually they take several for security).

Don't get me wrong: I am not saying it is impossible. But without taking into account the real conditions and without necessary measuring equipment I doubt you will make it by just blindly coding along ...

Have fun ....

schufti wrote:no, crystal frequency IS NOT 80MHz.
take a look and see: 26MHz

so what is the 80MHz? --> the cpu clock

how do you get 80MHz from 26MHz ??? not really a multiple --> PLL (cheap) so you will have phase jitter

What quality does the crystal have ??? probably low +/- --> ???ppm --> so the 80MHz will be ???

Temperature stability will be ???

As I wrote, your generated frequency needs to be within a window of several 10Hz +/- around the 77500Hz
stable for at least 2 minutes for the clock to detect one correct packet (usually they take several for security).

Don't get me wrong: I am not saying it is impossible. But without taking into account the real conditions and without necessary measuring equipment I doubt you will make it by just blindly coding along ...

Have fun ....

i have one frequencymeter and show 26MHz from pin special function, and 77kHz too.. let's see how ESP work.. i will post images later

The crystal in my nodemcu says 12 Mhz
You are right, without measuring equipment I am lost but it is just for fun and learning.
I'm learning a lot abour timers and interruptions with this proyect.
Well it is easy with a Arduino Uno or Attiny85, it will be fun that ESP8266 won't make it.

Thanks again for your comments, all of them are apreciated.

Get fun.

urbanze wrote:

schufti wrote:no, crystal frequency IS NOT 80MHz.
take a look and see: 26MHz

so what is the 80MHz? --> the cpu clock

how do you get 80MHz from 26MHz ??? not really a multiple --> PLL (cheap) so you will have phase jitter

What quality does the crystal have ??? probably low +/- --> ???ppm --> so the 80MHz will be ???

Temperature stability will be ???

As I wrote, your generated frequency needs to be within a window of several 10Hz +/- around the 77500Hz
stable for at least 2 minutes for the clock to detect one correct packet (usually they take several for security).

Don't get me wrong: I am not saying it is impossible. But without taking into account the real conditions and without necessary measuring equipment I doubt you will make it by just blindly coding along ...

Have fun ....

i have one frequencymeter and show 26MHz from pin special function, and 77kHz too.. let's see how ESP work.. i will post images later