Technical information
Opto DIO16 OPTO DIO Reference
directly replaced by UDN2981 drivers for output voltages in the
range 5 to 50 Volts. Whilst the 2984 drivers have built in output
transient suppression diodes, extra diodes are provided on card
the Opto DIO16 card for extra protection. The socketed 10k
resistor network RN14 should be left installed.
For normal operation, with UDN2984 chips installed, socket U26
contains an non inverting buffer chip 74LS541.
For inverse operation, an inverting buffer chip 74LS540 should
be installed in socket U26.
Sink Driver Output Connection.____________________________
ULN2804 Drivers.
The ULN2804 chips are high voltage, high current NPN
DARLINGTON drivers, output voltage range to 50 Volts, these
could be directly replaced by ULN2824 chips for output voltages
up to 95 Volts. The 2804 have open collector outputs. When
changing from 2984 to 2804 drivers note than the 2804 are
INVERTING drivers, thus to produce the same logical output
from a bit pattern written to the output port the 74LS541 chips
would have to be replaced by the inverting 74LS540 chips.
Remove the socketed 10k resistor network RN14.
For inverse operation, then an non inverting buffers chip
74LS541 should be installed in socket U26.
Opto DIO16 Memory Map.________________________
The Opto DIO16 has 8 dedicated output lines arranged as
one eight bit read/write register, 8 dedicated input lines arranged
as one eight bit read only register. Thus the DIO16 card
occupies 2 consecutive i/o addresses. The output ports is output
only, however the output register is read/write, writing to it sets
the level of the output lines, reading it provides a read back of
the previously written value. On power up the outputs are zero.
Inputting and outputting data to the port registers senses
and sets the values of the pins at the external connector.
Chapter 3 Page 33