atmega328 ad-channels send via i2c to stm32f407

opamps and voltage divider resistors don't take up much pcb space and cost pennies.

BTW this might be interesting for you: https://easyeda.com/pazi88/Arduino_Mega_2560-z92kCUO6o

http://www.youtube.com/pazi88

Re: atmega328 ad-channels send via i2c to stm32f407#46530

By fram - Tue Nov 17, 2020 8:35 pm

- Tue Nov 17, 2020 8:35 pm #46530

reason is you dont need op-amps

Ok, but you will probably need a voltage bus translator for your I2C bus, because STM32F407 is 3.3V running, and ATM328 is 5V running. Don't see the point to use a second µC...

GITHUB about my Custom Speeduino ECU: https://github.com/FRAMSPEEDUINO/CUSTOM_SPEEDUINO_ECU

Re: atmega328 ad-channels send via i2c to stm32f407#46534

By moonie223 - Wed Nov 18, 2020 7:13 am

- Wed Nov 18, 2020 7:13 am #46534

May as well just use a i2c/spi ADC at that point. Run it off 5.0V VDD and VCC, then do something to convert the logic level, depending on the speed of the communications could be simple or could be complicated...

There's a really nice little dual BSS138 package that works well for converting i2c logic levels. Otherwise I've had good luck just spending the money and using a nice chip like the max3390 for converting high speed SPI.

Re: atmega328 ad-channels send via i2c to stm32f407#46539

By tooly - Wed Nov 18, 2020 1:47 pm

- Wed Nov 18, 2020 1:47 pm #46539

hi,
i upload the projekt+schematic
viewtopic.php?f=16&p=46538#p46538

oelprinz.org

Re: atmega328 ad-channels send via i2c to stm32f407#46540

By JHolland - Wed Nov 18, 2020 2:53 pm

- Wed Nov 18, 2020 2:53 pm #46540

The ADCs in the STM32 are far superior to the single ADC in the Mega, you're just downgrading and adding complexity for no real reason.

Re: atmega328 ad-channels send via i2c to stm32f407#46541

By tooly - Wed Nov 18, 2020 3:54 pm

- Wed Nov 18, 2020 3:54 pm #46541

reason is to have independent lambda and dbw controller

oelprinz.org