ES51970(6000counts)
DMM Analog front end with Inrush
2.8 Frequency/duty cycle mode measurement
The default typical input impedance of frequency with duty cycle mode is 1MΩ. The MPU
could set control bit FRES=1 to change the input impedance down to 100kΩ. The MPU
send write command to select the frequency/duty cycle measurement function.
F3
F2
F1
F0
Measurement mode
Read data bytes
0
1
1
1
Hz + Duty mode
D0(0:18), D2(0:18), D3(0:18)
Note1: D0/D2/D3 all are binary format. ASIGN bit is ignored.
Note2: Set LPF1 = 1 to enable the smooth function for sine wave input automatically
Range control for frequency mode
FQ2 FQ1 FQ0
Full Scale
60.00Hz
600.0Hz
6.000KHz
60.00KHz
600.0KHz
6.000MHz
60.00MHz
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
Available minimum frequency input (Depends on ADC conversion rate setting)
C1
0
C0
0
FMIN(AC+Hz mode) FMIN(Hz+Duty mode)
4.00Hz
0
1
1
0
6.00Hz
4.00Hz
8.00Hz
1
1
10.00Hz
Frequency & duty cycle mode computed by D0/D2/D3 (if F_FIN = 1)
Flag
STA0=0
STA0=1
Range
STA1=1
STA1=0
60.00Hz
600.0Hz
FREQ=100000000/D3
FREQ=10000000/D3
FREQ=2000000/D3
FREQ=200000/D3
FREQ=400000000/D3
FREQ=40000000/D3
FREQ=32000000/D3
FREQ=25600000/D3
FREQ=800000000/D3
FREQ=160000000/D3
FREQ=256000000/D3
FREQ=204800000/D3
6.000KHz
60.00KHz
600.0KHz
6.000MHz
60.00MHz
FREQ = D0
Status Flag
LDUTY=1
LDUTY=0
Duty cycle (<60kHz)
10000-D2*10000/D3
D2*10000/D3
ver. 2.8
19
12/01/12
CYRUSTEK [ Cyrustek corporation ]
