How to reset an Atmel AT90CAN128 from software?

Jun 20, 2008 1 Replies
L

Hello all. I'm looking for a relatively clean way to code a software reset for an AT90CAN128 or ATMEGA128 microcontroller using C code (or C with assemby embedded) that will compile under the avr-gcc 3.4.6 compiler chain. Essentially, I want a function softReset() that I can call from my program when appropriate that will reset and reinitialize everything, just as if a POR had occurred or the reset pin had been pulled low. I am ok with the MCUSR register containing garbage after coming out of this reset. I'm trying to avoid using the hardware watchdog and just not petting it, since I think it has to be always on or always off, and I don't want to have to "pet" it while the rest of my program is running. Ideas?



-Will


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R

The watchdog is your friend and really, really ought to be part of your toolkit.

That said, the only other way to make it appear as if the power-on reset has occurred is ... to cause a POR. A "soft" reset by forcing a jump the reset vector will cause the code-side to be reinitialized but the processor's registers and peripherals won't be reset.

You can hook up an inexpensive supervisory IC (Microchip's MCP-130 is one example of many out there) to force a reset of known duration by triggering it from one of your processor's output pins.

Rich Webb Norfolk, VA
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