Product Info

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VTech Communications LTD.

R&D Department

The document is VTech’s proprietary information, Please do not disclose to third party without VTech’s consent

Ref. No.: 20191009 Version: 01 Date: 09 Oct, 2019 Page 25 of 33

The RST# pin is an active low reset. Assert the reset signal for a period > 5 ms to ensure a full reset.At reset the digital I/O

pins are set to inputs for bidirectional pins and outputs are set to tristate.

NOTE Reset can also be triggered by a UART break symbol if:

• Host interface is any UART transport

And

• PSKEY_HOSTIO_UART_RESET_TIMEOUT is set to a value more than 1000 A reboot function is also

available under software control.

9 Battery charger

The battery charger hardware is controlled by the on-chip application. The battery charger has 5 modes:

■ Disabled

■ Trickle charge

■ Fast charge

■ Standby: fully charged or float charge

■ Error: charging input voltage, VCHG, is too low

Transitions between the trickle charge, fast charge and standby modes are triggered by changes in battery

voltageand charger current.

Table 10-1 Battery charger operating modes determined by battery voltage and charger current

Mode

Battery charger enabled

VBAT_SENSE

Disabled

Trickle charge

Yes

> 0 and < Vfast

Fast charge

Yes

> Vfast and < Vfloat

Standby

Yes

Iterm and > (Vfloat - Vhyst)

Error

Yes

> (VCHG - 50mV)

Iterm is approximately 10% of Ifast for a given Ifast setting