Industrial Electronic Engineers, Inc.
SIZE
A
CODE IDENT NO.
05464
S03875–21–0214
Van Nuys, California
SCALE N/A
REV A
SHEET 19
5.2.1
Power–up Supply Requirements
Initialization may or may not be performed completely unless the rise time (t
RCC
) of the power supply is correct
at turn–on (1ms < t
RCC
< 10ms). Figure 11 represents the requirements of the power supply. Note that t
OFF
stipulates the minimum time that power can be OFF (t
OFF
> 1ms) during a momentary dip or when the power
supply cycles ON and OFF.
0.2V
4.5V
t
RCC
t
OFF
V
CC
Figure 11
Power Supply Requirements
5.2.2
External Reset Requirements
To utilize the optional external reset, the RESET pin must be held at ground (<0.5 Volts) for at least 10
milliseconds after the power supply is within the voltage tolerance. Figure 12 shows the module Reset circuit.
+5V
1k
3.3k
330
1uF
Microprocessor
Internal
Pull–down
J2–Pin 3
Figure 12
External Reset Circuit
5.3
Interface Signals
5.3.1
Serial Interface Signals
The display is designed to be operated by a standard RS–232 serial interface. The user can operate the
module with any interface which meets the following requirements for a "mark" condition and a "space"
condition. The user should observe generally accepted design rules when interfacing to the display.
Space Voltage
(V
RX
Data – V
RX
Data RTN)
+3.0 to +25.0 Volts
Mark Voltage
(V
RX
Data – V
RX
Data RTN)
–25.0 to +0.8 Volts
