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I'm designing a PCB with an ATmega328P (SMD) and two ADS1118 ADCs (also SMD) that will be connected to the ICSP pins of the ATmega328P. Will these two ADCs, in parallel with the MCU, pose a problem for bootloader flashing/MCU programming through the ICSP pins?

Do I need to add some switches to the PCB to disconnect the ADCs during programming?

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electronics
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  • This question and answers will help you: https://electronics.stackexchange.com/questions/76415/spi-device-prevents-isp-programming – MiNiMe Oct 22 '23 at 17:35
  • Decouple the DOUT of U1 with a series resistor of around 470 ohm for safety. This way the programmers wins if connected. Don't forget a proper pullup resistor for /CS. – Jens Oct 22 '23 at 17:36
  • @Jens thank you! I've planned to add 50 ohms resistors between U1 and the ATmega328 as suggested in the datasheet of the ADS1118. Will 50 ohms be enough or I must go with a higher value - 470 as you've suggested? – electronics Oct 22 '23 at 17:50

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