ver. 2.8

12/01/12

19

ES51995(6000counts)

DMM Analog front end with PEAK

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. 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

0

0

0

60.00Hz

0

0

1

600.0Hz

0

1

0

6.000KHz

0

1

1

60.00KHz

1

0

0

600.0KHz

1

0

1

6.000MHz

1

1

0

60.00MHz

Available minimum frequency input (Depends on ADC conversion rate setting)

C1

C0

0

0

4.00Hz

4.00Hz

0

1

6.00Hz

1

0

8.00Hz

1

1

10.00Hz

Frequency & duty cycle mode computed by D0/D2/D3 (if F_FIN=1)

Flag

STA0=1

STA0=0

Range

STA1=1

STA1=0

60.00Hz

FREQ=100000000/D3

FREQ=400000000/D3

FREQ=800000000/D3

600.0Hz

FREQ=10000000/D3

FREQ=40000000/D3

FREQ=160000000/D3

6.000KHz

FREQ=2000000/D3

FREQ=32000000/D3

FREQ=256000000/D3

60.00KHz

FREQ=200000/D3

FREQ=25600000/D3

FREQ=204800000/D3

600.0KHz

FREQ = D0

6.000MHz

60.00MHz

Status Flag

LDUTY=1

LDUTY=0

Duty cycle (<60kHz)

10000-D2*10000/D3

D2*10000/D3