Data Translation DT9840 Series, User Manual

Page: 88 / 130

Appendix A
88
Digital Input Specifications
Table 22 lists the specifications for the digital input subsystem.
Table 22: Digital Input Subsystem Specifications
Feature Specifications
Number of lines
For DT9841 and DT9841E:
24
(
Ports 0, 1, and 2 each consisting of 8 programmable
digital I/O lines)
a
For DT9841-VIB:
16
(
Ports 0 and 1 each consisting of 8 programmable
digital I/O lines)
a
a. When port 0 is configured for digital input, you can configure the software to interrupt the host
computer whenever any of the bits changes state. In addition, to reduce noise and minimize false
state changes, you can enable a 10 ms deglitch function for port 0 when it is configured for digital
input.
Termination 22 k
Ω
pull-up series 22
Ω
Input type HCT
+5 V tolerant Yes
Input load 22 k
Ω
pull-up to 3.3 V
Inputs
Input type:
Input load:
High-level input voltage:
Low-level input voltage:
High-level input current:
Low-level input current:
Level sensitive
1 (HCT)
2.4 V minimum
0.8 V maximum
0
μ
A
0.2 mA
Back EMF diodes Yes