Tagged Questions

5
votes
2answers
319 views

AVR interrupt service routine not executing as fast as expected (instruction overhead?)

I'm developing a small logic analyzer with 7 inputs. My target device is an ATmega168 with a 20MHz clock rate. To detect logic changes I use pin change interrupts. ...
7
votes
2answers
262 views

Any reason not to use Timer0 on AVR?

Just a basic question... For arduino/avr/ATMega328 I find lots of examples using Timer1 (there's even a whole library for it) but rarely any that utilize Timer0 (or Timer2). Now, I know that using ...
1
vote
3answers
253 views

Dimming multiplexed LEDs

I'm multiplexing 32 LEDs in a 4:8 configuration on an ATMega328 and am trying to dim them with what is probably a completely naive understanding of PWM. Note: I'm multiplexing them directly with 12 ...
3
votes
2answers
313 views

Can't set to Fast PWM OCRA mode

Trying to have Fast PWM mode when TOP == ORCA. Works fine with OCA toggle (measuring correct frequency), but doesn't work in ...
1
vote
1answer
257 views

Arduino low power consumption and multiplexer

I've got a project that uses an Arduino with the LadyAda audio shield and a multiplexer to play sounds in response to button presses. I'm planning on using a MAX667 voltage regulator which has a low ...
2
votes
4answers
320 views

What can be the cause of an exceptionally large latency for the UART receive interrupt?

I receive data on the UART, using an 8-bit atmega, usually around 5 bytes connected, then a long pause. The total time for one byte (with start+stop bits, I don't use parity) is 160 us. However, the ...
4
votes
2answers
354 views

Moving the code and interrupt locations in Arduino

I need to be able to choose between two Arduino apps running on an atmega 1280 (megaavr) at boot time. Therefore I need to move one of those apps to a different location in program memory, and I need ...
3
votes
2answers
2k views

Does anyone have any examples or suggestions utilizing Atmel's ATMEGA2560 and external interrupt's?

I am trying to utilize an ATMEGA2560 and it's interrupt. I have some code that must execute until a button is pressed at which time I need the code to stop and wait for another button press to ...