Ciao a tutti, mi chiamo Giuseppe, ho 66 anni, sono un appassionato di elettronica, sto cercando qualcuno che mi aiuti a fare uno schema elettrico, ho un oscillatore a 10Mhz (OCXO) con un'uscita sinusoidale a 2,5Vpp, devo convertirlo in un'onda quadra TTL a 3V, l'uscita ad onda quadra TTL deve entrare nel PA15 del STM32F411CEU6 perché il contatore vuole un'onda quadra TTL, scusami per l'inglese, sto usando Google Translate. Grazie in anticipo.


Mod:translated.

Hi everyone, my name is Giuseppe, I'm 66 years old, I'm an electronics enthusiast, I'm looking for someone to help me make a circuit diagram, I have a 10Mhz oscillator (OCXO) with a 2.5Vpp sinusoidal output, I need to convert it to a 3V TTL square wave, the TTL square wave output needs to go into the PA15 of the STM32F411CEU6 because the counter wants a TTL square wave, sorry for the English, I'm using Google Translate. Thanks in advance.

 

Use a 74HC14, 74LVC1G14, 74LVC1G17 etc. connect the signal to the HC14 input through a resistor of at least 1k.

 

LTspice sim below of a circuit using a 74HC14:

For faster output rise/fall times, use the 74LVC1G devices

 

LTspice sim below of a circuit using a 74HC14:

For faster output rise/fall times, use the 74LVC1G devices

View attachment 349288

Grazie, ho provato a renderlo uguale al PA15 del STM32F411CEU6, purtroppo non accetta, non so cosa fare, ci sto provando ormai da 5 giorni ma sempre con esito negativo, chiedo gentilmente se c'è un'altra soluzione. Grazie per la vostra disponibilità.
Giuseppe

Google translation:
Thanks, I tried to make it the same as the PA15 of the STM32F411CEU6, unfortunately it does not accept, I do not know what to do, I have been trying for 5 days now but always with a negative result, I kindly ask if there is another solution. Thanks for your availability.
Giuseppe

Moderators note: this is an english only site.
Please use only english over here

 

The easy way to get the three volts out is to use a CMOS IC from that list and power it with 3 volts.

 

LTspice sim below of a circuit using a 74HC14:

For faster output rise/fall times, use the 74LVC1G devices

View attachment 349288

I got a question, why u connect the sine wave into that resistor divider? 10k/25? whats the purpose? then that resistor u use it to limit the current before entering the 74HC14 but u will have a voltage drop on it.

 

I got a question, why u connect the sine wave into that resistor divider? 10k/25? whats the purpose? then that resistor u use it to limit the current before entering the 74HC14 but u will have a voltage drop on it.

The input current is negligible as long as the input voltage is above zero and below the supply voltage of the 74HC14, so there is no voltage drop.
Outside that voltage range the internal input protection diodes conduct and the resistor limits the current to protect the diodes.

 

[CITAZIONE="crutschow, post: 1984580, membro: 19451"]
La corrente di ingresso è trascurabile finché la tensione di ingresso è superiore a zero e inferiore alla tensione di alimentazione del 74HC14, quindi non si verifica alcuna caduta di tensione.
Al di fuori di tale intervallo di tensione, i diodi di protezione di ingresso interni conducono e il resistore limita la corrente per proteggere i diodi.
[/CITAZIONE]
The diodes internally to the 74HC? and how u get 5V at output tho? i didnt get it

 

The input current is negligible as long as the input voltage is above zero and below the supply voltage of the 74HC14, so there is no voltage drop.
Outside that voltage range the internal input protection diodes conduct and the resistor limits the current to protect the diodes.

voltage divider i meant this

 

Someone says that you can use a LT1719, they say it is more precise and safe, is it true? If it is true I have a diagram on how to use it.

 

10 MHz signal into PA15.
What are you trying to achieve?
How do you determine if it works or not?
You don’t need any external ICs to do this.

 

I'm making a 10Mhz PLL GPSDO and I have an OCXO with a sine wave output, I need to use an internal counter of the STM32F411CEU6, the counter input needs a 3.3V TTL square wave.

 

You can use a CD4009 voltage shifting inverting hex buffer OR a CD1010 voltage shifting non-inverting hex buffer. Both devices have separate supply connections for the input and output sections. Certainly this would be a minimum parts count method of achieving your requirements. These buffers will also square-up the sine wave fairly well.

 

You can use a CD4009 voltage shifting inverting hex buffer OR a CD1010 voltage shifting non-inverting hex buffer.

At 10MHz?

 

At 10MHz?

Probably not, with a 50 ns response time, 100ns Max. so try the 74ACT14, and on te output use a 1K series resistor and clamp diodes to limit the high end to about 3 volts.

 

Probably not, with a 50 ns response time, 100ns Max. so try the 74ACT14, and on te output use a 1K series resistor and clamp diodes to limit the high end to about 3 volts.

can you give me a diagram on how to do it, thank you very much.

 

https://forum.allaboutcircuits.com/...justing-frequency-counter.204571/post-1965766

My version of a 10MHz sine to 3.3V TTL square wave converter.






Tested to 40MHz.


https://github.com/nsaspook/gpsbuf/tree/no_buffer

 

OK, I did not get very far in looking at different devices. My experience has been CMOS at lower frequencies/data rates. That was all that was ever needed and that was fine with me.

 

https://forum.allaboutcircuits.com/...justing-frequency-counter.204571/post-1965766

My version of a 10MHz sine to 3.3V TTL square wave converter.

View attachment 349745
View attachment 349748

View attachment 349746

Tested to 40MHz.
View attachment 349747

https://github.com/nsaspook/gpsbuf/tree/no_buffer

thank you very much, I'll let you know if it's ok

 

Why can you not input the sinewave into the digital input?
Does the input know the difference between a sinewave and a square wave?
(I am trying to understand why you think that you cannot do this, just for my clarification.)

What is the difference between a digital signal and an analog signal?
A digital signal is analog.