Richardcavell
Member
Hi, everyone.
I've designed a circuit for an AVR microcontroller. Could you please check and make sure I've done it correctly? I'm an amateur and this is the most complex thing I've ever designed.
1. I've aimed for about 20 mA through LED1 and LED2. Is that about right?
2. What do I do for Q1 and R4?
3. The idea is that the output of one AVR will be carried on the DB-25 connector and become the input to another AVR. If I connect a general purpose I/O pin to another one, do I need to put a resistor between them?
4. Does the LED2 connection look right? Its output will come off a GPIO pin of another AVR. Do I need to put a transistor in there to give it enough current?
5. The idea of the DB-25 connector is that this AVR circuit will be independent of the other, but can be connected at any time. Each circuit has its own power supply. When the circuits are connected, GND for both circuits will suddenly be matched up. Is there anything I need to do to account for sudden potential differences?
Richard
I've designed a circuit for an AVR microcontroller. Could you please check and make sure I've done it correctly? I'm an amateur and this is the most complex thing I've ever designed.
1. I've aimed for about 20 mA through LED1 and LED2. Is that about right?
2. What do I do for Q1 and R4?
3. The idea is that the output of one AVR will be carried on the DB-25 connector and become the input to another AVR. If I connect a general purpose I/O pin to another one, do I need to put a resistor between them?
4. Does the LED2 connection look right? Its output will come off a GPIO pin of another AVR. Do I need to put a transistor in there to give it enough current?
5. The idea of the DB-25 connector is that this AVR circuit will be independent of the other, but can be connected at any time. Each circuit has its own power supply. When the circuits are connected, GND for both circuits will suddenly be matched up. Is there anything I need to do to account for sudden potential differences?
Richard
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