ST default firmware

VT5365

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3

ST default firmware

3.1

Switches (GPIO 3 - 7)

The VT5365 supports up to 5 switch inputs with the default firmware. These switches

provide the standard mouse functions of LEFT, RIGHT and MIDDLE as well as the

advanced functions of BACK and FORWARD. The switch inputs are all active LOW. An

external pull-up resistor is required between the switch input and the VBAT (1.8 V) supply.

3.2

Scroll wheel (GPIO 1 & 2)

The VT5365 supports the use of an external mechanical shaft encoder with quadrature

outputs to act as a scroll wheel. Pull-up resistors are required between the ZA and ZB

outputs of the shaft encoder and the VBAT supply. Note that the two quadrature outputs ZA

and ZB are not interchangeable and must be connected correctly.

3.3

GPIO 0 - internal/external RF selection + low battery output

3.3.1

Internal/external RF selection

The state of GPIO 0 is detected at power-up:

●

If GPIO 0 is LOW, the RF output will be baseband serial data and an external RF

modulator will be required.

●

However, if GPIO 0 is HIGH at power-up, the internal RF modulator will be enabled and

the output will be digitally modulated 27.045 MHz FSK. In this case, very minimal

external circuitry is required for filtering and amplification, and the overall system can

be achieved using a single 12MHz crystal.

For more details and schematics, please refer to the STV-365-R0X user manuals.

3.3.2

Low battery output

After power-up, if a low battery condition is detected, GPIO 0 becomes an output that can

drive a low current LED.

If the battery goes below 0.8 V, GPIO 0 will be pulled low during RUNNING mode only (that

is, when the mouse is moving or during ZWheel/button presses), and goes to highZ in IDLE

or SLEEP modes. If the battery voltage goes above 1 V, GPIO 0 will stay highZ in all modes.

3.4

SGPIO 0 - power supply select

The VT5365 can be powered by either a single 1.8 V supply (single/parallel batteries) or a

2.0 V to 3.2 V supply (batteries in series).

Connecting SGPIO 0 to 0 V enables the direct drive, turning off the internal 1.8 V regulator.

While connecting SGPIO 0 to 1V8 allows the VT5365 to be driven at the minimal supply of

1.8 V, all internal regulators are used.