Hi, I have an ILI9341 that needs 3.3V logic so I use a bilateral converter to use with nano running from 5V usb.
The display needs a 5v supply and the nano 5V pin can supply it.
I tried a nano powered from 3.3V via power adaptor into VIN and connected the same display directly to the nano.
The display still needed a 5V supply from the power adaptor but worked fine showing in this case nano capable of running at 3.3V logic.
The display does have a solder jumper that shorts out the 3.3V regulator so display will run at 3.3V
Could maybe run on 3.6V battery. anyway less wiring than a logic converter and seems stable.
no experience with nano, but "nano" are actually mega328 isn't ? so .
adc has 2 input source referencess in mega328 ,
a) avcc which almost by definition you connect to power supply so avcc = vcc = 3.3 in your case
b) internal reference 1.1 where "255 = 1.1volt"
so in general answer is yes
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I connected a 10K pot across the 3.3v and gnd and the wiper to AN0 and printed the results on the screen and it printed 0 to 255 ...but the pot had more to turn... like it was using 0 to 5v but stopping at 3.3v being 255
Here is a video and sorry if I refer to the nano as a uno https://www.youtube.com/watch?v=5vkrBmguJnM&feature=youtu.be
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The idea was to use the ili9341 touch pins and this would be simpler wiring than using a logic converter but since the readad is strange then no wonder the touch did not work...again.
I got the mcufreind glcd on it's way and 2 nextions to use. I think I will retry them.
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gcb help mentions
Example 2 - Reading Reference Voltages:
When selecting the reference source for ADC on ATmega328 Great Cow BASIC will overwrite anything that you put into te ADMUX register - but this option allow you change the ADC reference source on Atmel AVR microcontrollers. You can set the AD_REF_SOURCE constant to whatever you want to use. It defaults to the VCC pin, as example you can set the Atmel AVR to use the 1.1V reference with this: #define AD_REF_SOURCE AD_REF_256 where 256 refers to the 2.56V reference on some older AVRs, but the same code will select the 1.1V reference on an ATmega328p
The example above sets the AD_REF_SOURCE to a variable, and then changes the value of the variable to select the source. With this approach, we also need to allow time to charge the reference capacitor to the correct voltage.
this refers to readad10. I am trying readad
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi, I have an ILI9341 that needs 3.3V logic so I use a bilateral converter to use with nano running from 5V usb.
The display needs a 5v supply and the nano 5V pin can supply it.
I tried a nano powered from 3.3V via power adaptor into VIN and connected the same display directly to the nano.
The display still needed a 5V supply from the power adaptor but worked fine showing in this case nano capable of running at 3.3V logic.
The display does have a solder jumper that shorts out the 3.3V regulator so display will run at 3.3V
Could maybe run on 3.6V battery. anyway less wiring than a logic converter and seems stable.
Last edit: stan cartwright 2020-09-10
A question. If I run a nano at 3.3V., what happens to readad. Is it still 0-255 ?
A question. If I run a nano at 3.3V., what happens to readad. Is it still 0-255 ?
ie is 3.3V = 255
no experience with nano, but "nano" are actually mega328 isn't ? so .
adc has 2 input source referencess in mega328 ,
a) avcc which almost by definition you connect to power supply so avcc = vcc = 3.3 in your case
b) internal reference 1.1 where "255 = 1.1volt"
so in general answer is yes
I connected a 10K pot across the 3.3v and gnd and the wiper to AN0 and printed the results on the screen and it printed 0 to 255 ...but the pot had more to turn... like it was using 0 to 5v but stopping at 3.3v being 255
Here is a video and sorry if I refer to the nano as a uno https://www.youtube.com/watch?v=5vkrBmguJnM&feature=youtu.be
The idea was to use the ili9341 touch pins and this would be simpler wiring than using a logic converter but since the readad is strange then no wonder the touch did not work...again.
I got the mcufreind glcd on it's way and 2 nextions to use. I think I will retry them.
gcb help mentions
Example 2 - Reading Reference Voltages:
When selecting the reference source for ADC on ATmega328 Great Cow BASIC will overwrite anything that you put into te ADMUX register - but this option allow you change the ADC reference source on Atmel AVR microcontrollers. You can set the AD_REF_SOURCE constant to whatever you want to use. It defaults to the VCC pin, as example you can set the Atmel AVR to use the 1.1V reference with this: #define AD_REF_SOURCE AD_REF_256 where 256 refers to the 2.56V reference on some older AVRs, but the same code will select the 1.1V reference on an ATmega328p
The example above sets the AD_REF_SOURCE to a variable, and then changes the value of the variable to select the source. With this approach, we also need to allow time to charge the reference capacitor to the correct voltage.
this refers to readad10. I am trying readad
The answer was simple. Connect AREF pin to 3.3V supply.
now the pot swings 0 to 255 full rotation.
if the input was more than 3.3V then I break the the nano I guess.
https://drive.google.com/file/d/1c5U56F7KQ_heAS1NBbcmLhh2GMwQmuuZ/view
maybe try touch pins again.
edited no,touch still not working :(
Last edit: stan cartwright 2020-09-12