Measurement-computing USB-4301 Manuel d'utilisateur télécharger pdf (Page 16)

USB-4301 User's Guide Functional Details

Internal frequency values for different base frequencies

1.0000 MHz

1.6667 MHz

3.3333 MHz

5.0000 MHz

FREQ1

1.0000 MHz

1.6667 MHz

3.3333 MHz

5.0000 MHz

FREQ2

100.00 kHz

166.67 kHz

333.33 kHz

500.00 kHz

FREQ3

10.000 kHz

16.667 kHz

33.333 kHz

50.000 kHz

FREQ4

1.0000 kHz

1.6667 kHz

3.3333 kHz

5.0000 kHz

FREQ5

100.00 Hz

166.67 Hz

333.33 Hz

500.00 Hz

External sources

In addition to the five internal sources, the frequency source for the oscillator can be an input signal connected

to any of the five counter input pins (INP1 – INP5) or any of the five gate pins (GAT1 – GAT5). The input signal

can have a maximum frequency of 20 MHz on the counter input pins, and a maximum frequency of 7 MHz on

the gate pins.

The table below applies to all internal and external sources.

Oscillator sources

Source

Description

CTRINPUT1

Counter 1 input pin

CTRINPUT2

Counter 2 input pin

CTRINPUT3

Counter 3 input pin

CTRINPUT4

Counter 4 input pin

CTRINPUT5

Counter 5 input pin

GATE1

Counter 1 gate pin

GATE2

Counter 1 gate pin

GATE3

Counter 1 gate pin

GATE4

Counter 1 gate pin

GATE5

Counter 1 gate pin

FREQ1

Internal base frequency

FREQ2

Internal base frequency/10

FREQ3

Internal base frequency/100

FREQ4

Internal base frequency/1000

FREQ5

Internal base frequency/10,000

Divider (OSC divider)

The signal output from the OSC pin is the same frequency as the frequency source divided by a value from 1 to

16. For example, if you select a base frequency of 5.0000 MHz in InstaCal, and choose FREQ3 as the internal

frequency source (50.000 kHz from the Internal frequency values table above), and 8 as the oscillator divider,

the frequency of the signal at the OSC pin is (50.000 kHz / 8) = 6.2500 kHz.

Counter operation

Each of the five counters performs essentially the same function: their internal value either increments or

decrements on each rising or falling edge of their source signal. Since they are all 16-bit counters, they can

count up from 0 to 2

-1 = 65,535, or down from 65,535 to 0. When counting up, 65,535 is considered to be the

Terminal Count (TC); when counting down, 0 is the TC. There are a variety of configuration options that can

be used to unlock the power of this basic functionality.

1 2 ... 11 12 13 14 15 16 17 18 19 20 21 ... 26 27

Commentaires sur ces manuels

Pas de commentaire

Measurement-computing USB-4301 Manuel d'utilisateur Page 16

Commentaires sur ces manuels

Produits connexes et manuels pour Matériel Measurement-computing USB-4301