St25R3911B Power Down mode

[vaibh_p]

Hi , in ST25R3911B , as mentioned in datasheet in section 3.4 Electrical specifications, Table 10.1 , to enable the power down mode , setting following registers , will it make to power down mode ?

"Register 00h set to 0Fh(no clock on MCU_CLK), register 01h set to 80h (3 V supply

mode), register 02hset to 00h register 03hset to 08h, other registers in default state."

I am modifying this registers as soon as we read data from card.

And next time when we want to read the card , repeating all initializing sequence.

Will this work or else we have to configure another registers.

[Ulysses HERNIOSUS · Accepted solution]

Hi,

with default RFAL you will not need to disable MCU_CLK - it gets disabled by default analog configs in rfalInitialize().

Table 101 shows the electrical characteristics at VDD=3.3V. So of course sup3V bit is set for this supply. rfalInitialize() sets this bit automatically depending on current supply, no need to touch this bit in your code.

So in the end you only need to set register 02h to 0x00 and for recovering you can just call st25r3911OscOn() to re-enable the oscillator.

You could also call rfalInitialize() again but it will just re-write many registers which have kept their previous state (unless you cut the actual power supply of ST25R3911B.

Regards, Ulysses

[vaibh_p]

Thank you Ulysses