Cortex VEXnet Bedienungsanleitung PDF herunterladen (Seite 8)

CORTEX Microcontroller and Joystick Quick Start Guide

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5. Analog Information: Analog lines are input only and read about 62 (0.2 volts) when open. When connected to a 0 to 5v

source, such as the VEX Potentiometer, you will read from near 0 (0 volts) to near 1023 (5 volts).

a. Circuit details:

i. Analog input range is 0 to +5 volts.

ii. Analog circuit has a 470k pull-up to +5 volts, a series 10k resistor and a 20k resistor to ground.

iii. Analog inputs also have a 1000 pF capacitor to ground on the processor side of the 10k resistor.

iv. 3 dB bandwidth: 16 kHz.

v. Circuit connections as shown.

6. Digital Information: When congured as an input, digital lines have a weak pull-up. When congured as an output,

digital lines drive 0 volts for a low and 3.3 volts for a high.

a. Circuit details, Digital Ports 1 through 12:

i. Digital input range is 0 to +5 volts.

ii. Digital drive is primarily limited by the 1k series resistor, so it can output a 2v high into 2k-ohms to ground or a

0.8v low into 7k-ohms to 3.3v.

iii. Digital inputs also have a 1000 pF capacitor to ground on the processor side of the 1k resistor.

iv. 3 dB input bandwidth: 16 kHz.

v. Circuit connections as shown.

Analog Input

(Typical)

Weak Pull-up

In Processor

Digital Input Output

To Processor

20K

1000 PF

470 K

10 K

+5 V

3.3 V

1 K

Analog Port

Digital Port

b. Circuit details, SP Digital Port

i. Circuit SP is connected to the Digital-to-Analog-Converter (DAC) output of the User Processor.

ii. Factory default Hex le does not support the DAC output. Check your compiler for availability and use.

iii. SP is an Analog Output when congured by compiler. Drive is primarily limited by a 5 kilo-ohm internal processor

resistance and by the 100 ohm series resistor. Output swing of the processor into an open load is 0.2v to 3.1v,

typical.

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Cortex VEXnet Bedienungsanleitung Seite 8