This document describes how to effectively manage the operating states and modes of CR95HF and STRFNFCA devices to define an appropriate wakeup condition to reduce power consumption. CR95HF and STRFNFCA devices have two main functional domains. In Active mode, the devices can communicate with a host using one of the serial interfaces (UART or SPI) or with RFID tags using its RF capabilities. In Wait for Event (WFE) mode, the device remains quiescent while waiting for an external event. In this mode, a very low level of power consumption can be achieved. Application engineers can manage the wakeup conditions to optimize wakeup time or system power consumption.
This document describes tips for application engineers to effectively manage the operating states of CR95HF and STRFNFCA devices. It focuses on defining adapted wakeup conditions to return the device from low-power Wait for Event (WFE) modes, such as Hibernate or Sleep, back to the Active state to start communication with an external host.
The note details the two main functional domains: Active mode for communication and WFE mode for quiescent waiting. It provides specific instructions on using the Idle command to switch between states like Power-up, Hibernate, Sleep, and Tag Detector. Furthermore, it covers techniques to reduce power consumption by adjusting LFO frequency settings and configuring wakeup sources (timer, IRQ_IN pin, SPI_SS pin, or tag detection).
| LFO Period | 31.25 us |
|---|---|
| RF Carrier Period | 73 ns |
The Hibernate state has the lowest power consumption because most resources are switched off.
These devices communicate with a host using serial interfaces or with RFID tags using their RF capabilities.
The period of the device Low frequency oscillator is 31.25 microseconds.
The device returns to Ready mode in only a few milliseconds after receiving an external event.