>
> >To put it another way, if you run the chip with nothing connected, it will
> >draw 5mA [or less].  If you run it with 12 LED's sourcing 20mA each, it will
> >draw 245mA.
>
> Hi,
>
>    I didn't realise you could source so much current from a 16C65. Is
> the same true for a 16C84. My application uses 3 solenoids which pull 90
> mA max. I use 3 darlingtons to switch them; since space is at an absolute
> premium, could I dispense with the darlingtions and drive the solenoids
> direct from the port pins?

The 16C84 is listed my data book with the following specs:

Max Vss current: 150mA
Max VDD current: 100mA

Input/output clamp current: 20mA
Output current sunk, per pin: 25mA
Output current sourced, per pin: 20mA

Output current sunk, total of PA0-PA4: 80mA
Output current sourced, total of PA0-PA4: 50mA
Output current sunk, total of PB0-PB7: 150mA [same as device limit]
Output current sourced, total of PB0-PB7: 100mA [same as device limit]

Total power dissipation: 800mW

When you say your solenoids need 90mA max, is that each or is that total?
Will more than one be on at once?  If the 90mA is a total figure and each
solenoid only requires 30mA, you should be able to simply sink them off
port B, using two output pins each.  Otherwise, if 80mA each is enough,
but you only need one at a time, you could wire the solenoids in a "triangle"
with one vertex tied to PA0-PA3, one vertex to PB0-PB3, and the last to
PB4-PB7.  Then you could activate the solenoids as follows:

Sol #.   PA0-PA3  PB0-PB3  PB4-PB7
  1       Sink     Source    Off
  2       Sink      Off     Source
  3       Off      Sink     Source

Of course, then you only have one I/O port available for communicating with
the outside world, but such is life.

PS--Be *VERY* careful to ensure that you control any back-EMF from the
solenoids.  Solenoids can produce massive voltage spikes if not dealt
with properly.