Z-World eDisplay OP7200, Руководство пользователя

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18 eDisplay (OP7200)
3.3.2 Digital Outputs
The OP7200 has eight digital outputs, OUT0–OUT7, which are individually configurable
with the
digoutConfig
or
digoutTriStateConfig
software function calls as sinking
(up to 350 mA per channel) or as sourcing (up to 250 mA per channel). Figure 8 shows a
wiring diagram for using the digital outputs in a sinking or a souring configuration.
Figure 8. OP7200 Digital Outputs
All the digital outputs are in the high-impedance tristate when the OP7200 is initially
powered on or reset. The CPLD (U4) then enables either the sink control or the source
control to operate the digital outputs as sinking or sourcing, and thereby serves as a hard-
ware block to prevent both sinking and sourcing drivers from being activated at the same
time in a given channel.
Although the components are not installed, there is provision on the circuit board for the dig-
ital outputs to be pulled as a group to Vcc, +K, or to GND through 27 k
Ω
resistors. In spe-
cial circumstances, you may need to pull sinking outputs high to either Vcc or +K, or you
may need to pull sourcing outputs to GND, for example, when driving low-level logic sig-
nals. Pulling the digital outputs up to +K allows the current-sinking outputs to be used as
voltage outputs where their upper level is controlled by the voltage of +K. OP7200 series
+K
SINKING OUTPUTS
SOURCING OUTPUTS
+K
Current
Flow
Current
Flow
CPLD
SINK
CONTROL
SIGNAL
CPLD
SOURCE
CONTROL
SIGNAL