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Topic: Using the Atmega328p and ADS1115 (Read 312 times) previous topic - next topic

aidanb17

Hey guys,

im building a PCB using EasyEDA and was wondering if i could just get some verification that ive built this circuit correctly for proper operation of the Atmega328p and the ADS1115.

This circuit takes a differential reading from the ADS and displays it on an OLED.

I also added pins to upload to the 328 using TTL.

Ive never designed a circuit around the Atmega328 itself and ive created this using youtube videos.

WattsThat

#1
Jul 04, 2020, 07:48 pm Last Edit: Jul 04, 2020, 07:57 pm by WattsThat
While you provided connections for serial upload, you did not provide a means to reset the controller to activate the bootloader to do said uploading. Typically, it's a 100nf cap connected to the processor reset line so the serial adapter can reset the processor under program control to invoke the bootloader. All of this assumes the atMega328 was flashed with a bootloader prior to installation on the board. It's more common to bring out the ISP signals in a six pin header for all uploading via a Usbasp or stuff a usb to serial converter on the board for convenience. Just to be clear, are purchasing preloaded '328's? If not, you need the ISP pins brought out.

What kind of signals do you intend to measure with the ads1115? A non-changing dc level is all you'll be able to handle with the huge 470uf cap across the input. L1/L2: An inductor should have a value in Henries, 100 ohms is a resistance value. Typically, the inductors would be before the cap but I question the entire input configuration on the ADS1115. Please elaborate on what you'll be measuring since that configuration is downright odd.
Vacuum tube guy in a solid state world

jremington

#2
Jul 04, 2020, 09:04 pm Last Edit: Jul 04, 2020, 09:06 pm by jremington
Quote
This circuit takes a differential reading from the ADS and displays it on an OLED.
Keep in mind that both input voltages to the ADC must be between 0 and 5V at all times.

You need pullups on SDA and SCL.

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