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Forum: µC & Digital Electronics Check the Schematic Atmega328P with LoRa


von Mia (Guest)


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Hi,

can someone check if my Arduino with LoRa Circuit is correct please ? :)

I want to design PCB , wich start just when a one of two Signals  from 
J7 come ,
i use OR-Gate with MMBT5551 BJT to connect the GND1 from battery to GND 
in my circuit , and then i will send signal with LoRa chip .

Is my design correct ? will my Schematic working well ?

Lora need 100 mA max, uC need about 200 mA max
https://datasheet.lcsc.com/lcsc/1810190020_Changjiang-Electronics-Tech--CJ-MMBT5551_C2145.pdf

: Moved by Moderator
von Mia H. (miaaaa)


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sorry , that is the schematic

von N. M. (mani)


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Mia schrieb:
> Is my design correct ? will my Schematic working well ?

There ist no complete schematic.
So how can we check?

Do you realy need the 16MHz?
If 8MHz are OK you can remove the hole boost Part and you dont need 
Signal conversion between LoRa Module and uC.
By the way...where ist this done?

Edit:New schematic is added

: Edited by User
von Mia H. (miaaaa)


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N. M. schrieb:

> There ist no complete schematic.
> So how can we check?
I add it now here

> Do you realy need the 16MHz?
> If 8MHz are OK you can remove the hole boost Part and you dont need
i need 16MHZ

> Signal conversion between LoRa Module and uC.
> By the way...where ist this done?

i will connect it with cabel

> Edit:New schematic is added

von N. M. (mani)


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Mia H. schrieb:
>> Signal conversion between LoRa Module and uC.
>> By the way...where ist this done?
>
> i will connect it with cabel

And a cable makes signal conversion?

von Mia H. (miaaaa)


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RA-02 makes signal conversion and ready to connect directrly with 
Arduino( Atmega328p)

von Mia H. (miaaaa)


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N. M. schrieb:
> Mia H. schrieb:
>>> Signal conversion between LoRa Module and uC.
>>> By the way...where ist this done?
>>
>> i will connect it with cabel
>
> And a cable makes signal conversion?

RA-02 makes signal conversion and ready to connect directrly with
Arduino( Atmega328p)

von Mia H. (miaaaa)


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N. M. schrieb:
> Mia schrieb:
>> Is my design correct ? will my Schematic working well ?
>
> There ist no complete schematic.
> So how can we check?
>
> Do you realy need the 16MHz?
> If 8MHz are OK you can remove the hole boost Part and you dont need
> Signal conversion between LoRa Module and uC.
> By the way...where ist this done?
>
> Edit:New schematic is added


Do you mean like that ?

i make new schematic with 3.3 V

von N. M. (mani)


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Mia H. schrieb:
> RA-02 makes signal conversion and ready to connect directrly with
> Arduino( Atmega328p)

Nope.
Not with 5V Atmega (see Attachment).

von Mia H. (miaaaa)


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N. M. schrieb:
> Mia H. schrieb:
>> RA-02 makes signal conversion and ready to connect directrly with
>> Arduino( Atmega328p)
>
> Nope.
> Not with 5V Atmega (see Attachment).

Do you mean like that ?

i make new schematic with 3.3 V

von N. M. (mani)


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Mia H. schrieb:
> Do you mean like that ?

Yes, if 16MHz are not needed.

With this Change you dont need the Boost, no Signal Conversion between 
LoRa and uC and it is also better for battery mode because of lower 
power consumption.

von Mia H. (miaaaa)


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N. M. schrieb:
> Mia H. schrieb:
>> Do you mean like that ?
>
> Yes, if 16MHz are not needed.
>
> With this Change you dont need the Boost, no Signal Conversion between
> LoRa and uC and it is also better for battery mode because of lower
> power consumption.

thank you ,

will my logic with OR-Gate and BJT  working to start up the circuit?

: Edited by User
von Mia H. (miaaaa)


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with 3.3 on reset

von N. M. (mani)


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Your power supply isnt valid with the last changes.
V3 of CH340 needs input voltage in 3V3 Mode. It is no output.
So you have to generate 3V3 from your USB or the battery (see attachment 
CH340 or datasheet).
If you need an integrated 3V3 regulator, take a look at the FT232.

Mia H. schrieb:
> will my logic with OR-Gate and BJT  working to start up the circuit?

I dont think so. It is not very common to switch GND. I would recommend 
you to switch supply voltage 3V3 with a highside FET.
Also I would recommend you to put In_A and In_B to a static potential 
with a pulldown resistor. Because if the pins are floating there will 
happen some magic at the output of the OR-Gate. Perhaps it is also good 
to put some C there for better EMI behaveiour.

von N. M. (mani)


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N. M. schrieb:
> If you need an integrated 3V3 regulator, take a look at the FT232.

Ok, the FT232 can only deliver 50mA @ 3V3. So you need an external 
regulator.

von Mia H. (miaaaa)


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N. M. schrieb:
> N. M. schrieb:
>> If you need an integrated 3V3 regulator, take a look at the FT232.
>
> Ok, the FT232 can only deliver 50mA @ 3V3. So you need an external
> regulator.

can you give me example ? wich Fet can i use with Logic to startup my 
circuit ?

I edit it now

von N. M. (mani)


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I think something like in the attachment. Cant give you a good example 
(I am in the train at the moment).

I dont know if you realy need the 300mA...Common types in China Boards 
are AMS1117 or MCP1825 or ...

For highside switch take a look into the Forum. There are so many 
recommendations. 300mA is not so much for an FET. So a small one SOT23 
will do ist.

von Helmut -. (dc3yc)


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I would spend a crystal, even for 8MHz because the internal oscillator 
may not be very accurate.

von Mia H. (miaaaa)


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N. M. schrieb:
> I think something like in the attachment. Cant give you a good example
> (I am in the train at the moment).
>
> I dont know if you realy need the 300mA...Common types in China Boards
> are AMS1117 or MCP1825 or ...
>
> For highside switch take a look into the Forum. There are so many
> recommendations. 300mA is not so much for an FET. So a small one SOT23
> will do ist.

which P-Fet can working with 3V without drop-down the voltage ?

von r0bm (Guest)


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Mia H. wrote:
> which P-Fet can working with 3V without drop-down the voltage ?

https://embdev.net/topic/537580?goto=7079156#7079156

von Uskeliye U. (uskeliye46)


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RA-02 makes signal conversion and ready to connect directrly with

von Uskeliye U. (uskeliye46)


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I would spend a crystal, even for 8MHz because the internal oscillator
https://panoramacharter.ltd/

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