Latest thing to hit me is a temperature controller.  What I'm replacing (this is
 real
disgusting) is an embedded PC, using a STD CPU card, a A/D and digital output
 card, plus
a STD rack.  Its only job is to keep a heatsink at a set temperature.  Long
 story why it
was done originally like this....

OK, so I need to monitor two temperature sensors - one on the heatsink, one away
 from it
(free air temp).  Two choices - analog or digital.  Anyone had much experiance
 with the
new breed of parts, like the ones from Dallas or Analog Devices ?  I'd rather d
stay in the digital domain.

Setpoints and storage - I need a simple RS232 type interface with a PC to send
 down the
desired setpoint and to read back the two temperatures.  Storage of at least the
 setpoint
in nonvolatile memory is required.  Choice here is either eeprom or batt backed
 sram such
as the parts from Simtek (battery built inside the sram).

OK, the '84 gives me EEPROM, so thats nice.  No built-in UART. Has anyone does
 RS232 comm
with a PC an a '84 ?  I've never needed to implement a serial comm link.  The
 '84 would
work fine if I used a digital part.  Otherwise, the '71 could be used, but then
 I need to
add a current source and amp section.  Either could accomadate the control loop.

Comments anyone ?
hcooper@es.com