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TDA8035 external clock synchronous mode.

Question asked by Sylvain Bouriot on Nov 30, 2017
Latest reply on Feb 14, 2018 by Jonathan Iglesias

Hello,

am using TDA8035 chip as interface between smart card reader and micro controller. for synchronous and asynchronous card with a external clock generated by a micro-controller.

IN datasheet, we could read the follow sentence: "It is mandatory when an external clock is used, that the clock is applied on XTAL1 before CMDVCCN falling edge"

For asynchronous mode, it's not a problem.
But for synchronous mode, it's a problem, because, if  microcontroller send clock before CMDVCC falling edge, it will be not synchronized with card. (for example Microcontroller send 8 clocks, and card will receive 7 clocks (because card VCC is not yet active )

 

Have you any suggestion?

Sylvain

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