Low power mode management by the STM8TL5x STMTouch Library

AN3404

24/30

Doc ID 018847 Rev 3

7.1.5

Receiver configuration when disabled

The receivers are configured, when disabled, according to the

TSLPRM_PXS_INACTIVE_RX definition. The respective bit is reset in the receive enable

register (PXS_RXENR). The TSLPRM_PXS_INACTIVE_RX definition can be defined as 0

to drive the receivers to ground or it can be set to 1 to keep them floating.

When the receiver group A is selected, all group B receivers are configured according to the

TSLPRM_PXS_INACTIVE_RX definition.

The receiver PXS_RX pins are fully dedicated to ProxSense acquisition, i.e. they cannot be

used for general purposes and are configured and driven according to the ProxSense

configuration even if they are not used by any of the acquisition banks.

7.1.6

Transmitter configuration when disabled

The transmitters, which are defined in an acquisition bank and not enabled in the Transmit

enable register (PXS_TXENR), are configured according to the

TSLPRM_PXS_INACTIVE_TX definition. The TSLPRM_PXS_INACTIVE_TX definition can

be defined as 0 to drive the transmitters to ground or it can be set to 1 to keep them floating.

The GPIOs which support the transmitter (PXS_TX) alternate function, but which do not

belong to any acquisition bank or acquisition transmitter definition (example, BANK_x_TX)

are not configured by the STM8TL5x STMTouch Library. It is the responsibility of the

application code developer to configure the GPIOs which are not used for ProxSense

acquisition.

7.2

Practical code example

Section 7.2 presents two code examples. Both are based on the STM8TL5x STMTouch

Library. The first example (see Section 7.2.1: Low power management with all acquisition

banks) is a general case using all the acquisition banks as defined by default. The second

example (see Section 7.2.2: Very low power management with proximity detection)

configures the system in a very low power mode using Active-halt mode, with the AWU and

ProxSense waiting for a proximity detection.

7.2.1

Low power management with all acquisition banks

This example shows how to perform all bank acquisitions with minimum code executed by

the application and a maximum time spent in wait mode.