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TRF7970A timing between EN pin High and SOFT_INIT direct command

Sungho Kim
Prodigy 155 points
Other Parts Discussed in Thread: TRF7970A

Hi all~ this Sungho from LG electronics

I have some questions about EN pin and TX_OUT.

After EN pin(TRF_ENABLE) is ON...How long should I have to wait for stable operations of TRF7970A.

When I put some short time ( < 1ms ) I can get square wave(6.77MHz) from TX_OUT after CHIP_STATE_CONTROL(0x21) command.

But if I put long time( about 3ms or more)....I can`t get square wave from TX_OUT...

As I know...there should be 2 or 3 ms delay between EN high and SOFT_INIT...

I really want to know the exact timing.

And one more question...when I set NFC_TARGET_PROTOCOL register with 0x24 (ISO14443 A)..there disappear TX_OUT square wave...is this right?

Somebody help me please~

Thanks.