TC818A Просмотр технического описания (PDF) - Microchip Technology
Номер в каталоге
Компоненты Описание
производитель
TC818A Datasheet PDF : 24 Pages
| |||
TC818A
3.17 “Buzzer” Drive Signal
The BUZ output (Pin 4) will drive a piezo electric audio
transducer. The signal is activated to indicate an input
over range condition for current and voltage measure-
ments, or continuity during resistance measurements.
During a resistance measurement, a reading less than
19 on any full scale range causes a continuous 4kHz
signal to be output. This is used as a continuity
indication.
A voltage or current input measurement over range is
indicated by a noncontinuous 4kHz signal at the BUZ
output. The LCD most significant digit also flashes and
the three least significant digits are set to display zero.
The buzzer drive signal for over range is shown in
Figure 3-14. The BUZ output is active for any reading
over 2000 counts in both manual and auto-range oper-
ation. The buzzer is activated during an extended res-
olution measurement.
The BUZ signal swings from VCC (Pin 28) to DGND
(Pin 58). The signal is at VCC when not active.
The BUZ output is also activated for 15ms whenever a
range change is made in auto-range or manual opera-
tion. Changing the type of measurement (voltage, cur-
rent, or resistance), or measurement option (AC/DC,
Ω/LOΩ), also activates the buzzer output for 15msec.
A range change during a current measurement will not
activate the buzzer output.
FIGURE 3-14:
TC818A TIMING WAVEFORM FOR BUZZER OUTPUT
122ms
122ms
610ms
122ms
122ms
122ms
VCC
Digital Ground
1 Conversion
4kHz Signal
Noncontinuous Buzzer Signal Indicates Input Over Range
Power-up
VIN = 250mV
Change
Change
Change
4000 8000 12000
Range
Range
Range
Change Input
VIN = 3.2V
INT
Integrate
TSC818A
Signals
DEINT
AZ
BUZ
(Pin 4)
1000 Clock
Pulses
100ms
1638.5
CP
122ms
2000
CP
250CP
Auto-Ranging
200mV
Range
Over Range
2V
Range
In Range
250CP
2V
Range
In Range
2500CP
250CP
3000CP
Manual Range
200mV
Range
Extended
Range
2V
Range
In Range
2V Range
Out of Range
4kHz 4kHz 15ms
One Cycle of
Over Range Buzzer
Buzzer Activated due
to Power-up
15ms
15ms
Due to Manual Due to
Range Change Range Change
4kHz 4kHz
122ms
Buzzer Activated due
to Previous Conversion
Over Range
610ms
Buzzer Activated
due to Previous
Conversion
Over Range
DS21475B-page 18
© 2002 Microchip Technology Inc.
Share Link: 