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Topic: ATMega328-Based Euro Module Trigger Output Protection (Read 392 times) previous topic - next topic

toneburst

May 29, 2015, 12:40 pm Last Edit: May 29, 2015, 12:42 pm by toneburst
Hi,

I'm planning a Eurorack synthesiser module, driven by an ATMega328 chip, with Arduino firmware.

The plan is to have 4 'digital' trigger/pulse outputs, driven by digital output pins on the ATMega, plus 4 DAC outputs, driven by two MCP4822 dual-channel 12bit ICs.

I've been looking at schematics of similar units, and some designs use buffer ICs to protect the MCU pins, and some have no protection other than a current-limiting resistor. I just wanted to seek advice on whether buffering is really necessary.

My initial though was to use something like an 74HC125 quad buffer for the trigger outs, but maybe this is overkill for a Eurorack environment.

Re. the DAC outputs, my plan was to use a quad op-amp to boost the 4.096V output of the DAC up to the 0>5V range. Would I need any additional output protection to protect the DAC and MCU?

I'm trying to keep the circuit as simple as possible, because I'm new to circuit design, but obviously, I'm anxious to ensure that the ICs are protected as much as required by the Euro environment, where a variety of signals could potentially be patched into the module.

Sorry for the stupid questions. I'm a noob..

a|x

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