Internal RC Oscillator

[juggie]

I'm using an AVRcam version 1.3 and I'd like to setup a printf function. In order to do this I'd like to know the Internal RC Oscillators operating frequency. The documentation mentions that only a baud rate of 115.2kbps is supported on the serial port but not the internal RC Oscillator frequency.

Thanks

Juggie

[Guest]

A couple of things here: There are a few routines in the AVRcam firmware to support the building and sending of textual debug messages out the serial port. These are a far cry from a full-fledged printf(), but they work just fine for sending byte buffers out the serial port.

The internal oscillator on the mega8 is not being used at all. The oscillator signal that drives the mega8 comes from the OV6620 camera module, and runs at 17.7 MHz. This is why you don't see a standard crystal on the board. This is required for the system to work properly.

Remember, the serial port is dedicated (in normal use) to supporting the AVRcam interface protocol. Thus, adding additional printf messages that go out the serial port essentially break the pre-defined protocol, so you'll have to show care in how they are used.

Another solution may be to bit-bang a serial port out another i/o line on the mega8. However, it is unlikely that you will be able to match the timing to a standard baud rate since there are other critically timed elements in the system that can't be interrupted.

Maybe a better question...what is it that you'd like to send out the serial port, and why?