I want to drive the coils of a latching relay from an AVR. The spec on the relays is 45mA, nominal, during the switching pulse. These are dual-coil DPDT latching relays, so you pulse one coil to switch it to one state, pulse the other coil to switch to the other state, and in between pulses the relay mechanically latches so there is no current drain.
So... the handy AVR spec sheet says 20mA max per I/O pin guaranteed, "although they may drive more", and no more than 100mA for all ports together. I'm thinking I could abuse this specification thusly: tie two output pins together to get a low-impedance source of 40+ mA, and use the pair to drive a coil.
Of course, any software bug could toast the I/O drivers if it manages to put the output pins into two different states -- it would be nice to protect against that. I can't afford 0.6V drop for protection diodes, or the relays won't latch reliably.
Any better ideas out there?