Tue Jul 16 18:14:02 EDT 2013

Reading the Atmel CCID app note

It seems best to first get the cardreader to work.  Help should be
available, and knowledge gained is useful for the phone side


* How does it provide clock to card?

US_BRGR contains 13 = 48MHz / 3.7MHz.  It looks like that's the clock
presented to the device.  This particular value corresponds also to
9600 baud using the default clock divisor or 372, so it can support
both self-clocked and clocked cards.

* What about bootup sequence?

The appnote mentions the tb time delay necessary to bring up the sim
card.  However, the "for" loop seems a bit weird:

    // tb: wait 400 cycles, 3.58MHz => 80µs 48000000Hz  (3840)
    for( i=0; i<(120*(BOARD_MCK/1000000)); i++ ) {

[1] http://www.atmel.com/Images/doc6348.pdf‎