"Graham Davies" <[EMAIL PROTECTED]> wrote: >> This is the standard way for driving LEDs, the micro >> can sink more current than it can source ...
> This isn't really true. It used to be true by the time the STK500 has been designed. All the early AVRs also worked that way (usually being able to sink about twice the current they could source). Also keep in mind that the STK500 was even intended for some MCS51 controllers (AT89S51 IIRC), and the MCS51 in general can *only* sink current on its outputs, not source. They don't have a data direction register but only pullup resistors and a pull-down output driver transistor. (At least, that's what I've read about them. I never really used MCS51 myself.) -- cheers, J"org .-.-. --... ...-- -.. . DL8DTL http://www.sax.de/~joerg/ NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-) _______________________________________________ AVR-chat mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-chat
