The Tecmar S-100 D/A board was designed for applications requiring high
speed accurate digital to analog conversion including real time
applications.
This board supported four independent high speed digital to analog
converters (DACs) with associated latches. Each DAC
operated completely independent of the rest. The DACs
have a conversion time of 3 usec which enabledthem to operate at maximum
computer speed. A 12 bit latch drives the inputs of each
DAC. Another 4 bit latch for each DAC holdd the four new
most significant bits waiting for the arrival of the new least
significant byte. This allowed the DAC to hold its
previous value until an entire new word was presented to it.
All the latches were set to zero by reset. To modify the
contents of a latch, and hence the output of a DAC, it was necessary to send
two bytes to the device. The input was a 12 bit two's
complement number. User selectable output ranges of 0 to
+5V, 0 to +10V, ±2.5V, ±5V, and ±10V were available.
The user had the option of adjusting offset and gain through external pots.
The board could be addressed as I/O ports or memory mapped.
Only four lines of software were required to program these DACs!
The manual for this unique board can be obtained
here.
Tecmar provided a Fortran library of sub-routines to use with this board.
This manual can be obtained
here.
