If you are interested in using interrupts, you must read the section on the individual interrupt pins very carefully, as they have different capabilities, especially where wake/sleep states are concerned. I just want to save others the same headache, if they're doing something similar to me. The processor data sheet is the very best source of information about all aspects of the MCU. Can I a) get confirmation that these pins can't be pulled LOW with a digitalWrite like most others, and b) suggest that this be added to the Mega's documentation page in the playground? The point is, this behavior seems to be very different from how the interrupt pins on (for example) pins 18 and 19 work, where I can set them as LOW or HIGH inputs however I like and they behave accordingly. What I do seem to have found (see this thread) is that SDA and SCL have internal pullup resistors that you have to compensate for with external pulldown resistors (or more pullup ones? I'm seeing conflicting statements from people running into this issue). I do a digitalWrite(SDApin,LOW) after setting the pinMode to INPUT, but they still read HIGH even if they're not attached to anything. Specifically, I can't seem to configure those pins to input LOW. I'm trying to use the external interrupts on pins 20 and 21 (SDA and SCL), and I'm noticing that there's some unpredictable behavior that doesn't seem to be officially documented anywhere. The Arduino reference for attachInterrupt command gives this chart for interrupts and pins on the Mega board: BOARD INT.0 INT.1 INT.2 INT.3 INT.4 INT. If yes, how define it if the programming references is "attachInterrupt(digitalPinToInterrupt(pin), ISR, mode)"īut, an external clock "in someway" is not like an "external interrupts", I 'm not sure to have transfer what i mean.I'm working with a Mega 2650. It has the same ATmega2560 processor and. This board is a shrunk version of the Arduino Mega 2560 Rev3 and is manufactured by Seeed Studio. Interrupts: The processor has 6 interrupt pins that can be used to trigger events in response to external inputs.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |