Customizable firmware

VT5365

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4

Customizable firmware

The VT5365 features 4 kBytes of code space that is held in RAM. The RAM can be

uploaded at power-up from an external EEPROM (via the on-chip I2C master module) which

can be programmed with customer specific firmware. Please contact ST for more details.

The EEPROM must be connected to the SDA and SCL pins of the VT5365. The EEPROM

cannot be programmed by the VT5365 itself and must be pre-programmed before being

fitted to the final PCB. This sequence is only performed once at power-up, (for example,

when the batteries are replaced).

4.1

GPIO management

There are up to 9 GPIOs available for customization: GPIO 0 - 7 and SGPIO 1 (SGPIO 1 -

output only, if not being used as a DCDC controller output to supply VLED, see Section 3.5:

SGPIO 1 - VGate).

SGPIO 0 is not available for customization as it is used as the Power Supply Select (see

Section 3.4: SGPIO 0 - power supply select).

4.2

Battery level monitoring

In the default firmware, the low battery level is set at 0.8 V with 200 mV hysteresis. This level

can be customized to be set from 0.6 V to 1.6 V in steps of 3.9 mV (1 V / 256).

4.3

Power mode time constants

The following power management time constants are also available for customization:

1.

The time before the mouse goes from one mode to the next i.e. from RUN to IDLE1 or

from IDLE 1 to IDLE 2. Minimum time between modes is 50 ms.

2.

RUN mode frame rate, up to a maximum of 10 Kfps.

3.

Speed at which the frame rate changes occur: low / medium / high frame rate.

4.

IDLE and SLEEP times, for example increase or decrease IDLE 2 off time from 100 ms.

Minimum ‘off time’ = 10 ms.

4.4

RF protocol

If required, the ST 27 MHz RF protocol can be replaced by the customer’s own protocol.

Please contact ST for more details.