Lpc2000

Andrew Berney wrote:
> Does anybody know if the UART TX line on the LPC2129 is capable of supplying
> 2.2mA, as I need it to drive an optocoupler for isolation

Yes, I have implemented isolated coms using HP2531s via 220R resistors 
without any problems. Vol/Voh are not as relevant as Iol/Ioh when 
driving leds and optos. The values given in the datasheet of 4ma just 
means that you can draw that much and still have the output voltage 
within logic levels *if* you were also driving other logic inputs.

  In your case it doesn't matter if the voltage is not at a logic level 
as long as it supplies the current required (within limits). CMOS 
outputs are very forgiving when driving low-resistance loads, just don't 
expect it to maintain logic highs and lows if you push it.

*Peter*