ISO7816 on LPC11u68 in 115200 baudrate

[mahmoudhosseini]

Hi every one,

we want to try lpc11u68 for contacting with a ISO7816 based smart Card.

As you know this required using usart0 peripheral in iso7816 mode,Also clock pulses(CLK pins) must be generated separately(maybe using (SCTimer/PWM).

Does any one know whats maximum frequency SCTimer can generate?

I think for transitiving  in 115200 baud-rate we need 42.96 MHZ of clock frequency, Can SCTimer toggle a pin with this frequency?

As a other way Can we set Fi & Di parameters of ATR in any bigger value than 372 for transferring more data in the same clock frequency?

WBR.

[mahmoudhosseini]

I'm using a standard java-card(2.2.2)  which actually is asynchronous smart card.Based on your code after running below code:

CardClockOn(); /* Start clock at Ta */

//-----------------------------definition of CardClockOn function----

static __INLINE void CardClockOn(void)
{
// SC_PWM->TCR = _BV(0);
LPC_IOCON->PIO0_17 |= 0x03; /* UART SCLK */
}

As you can see inside body of CardClockOn(),only usart_clock function assign to the p0.17 and that's all,

Then how this cause clock generation on the p0.17 pin ? I also checked this pin with logic analyzer and there not any lock frequency on this pin.

-----------------

Also user manual explicitly said :

Synchronous mode should not be used with smart card mode.

Then how we can use USART0_Clock pin for providing clock to the card?

---------

Also from 11.7.8 Smart card mode(user manual)

The USART0 SCLK pin will output
synchronously with the data and at the data bit rate and may not be adequate for most
asynchronous cards.

With best regards.

[mahmoudhosseini]

Thanks for excellent answer,but how non-exact clock frequency does not affect to successful transition ?As I know new smart cards only use this clock pulses for synchronizing .Then I think any differences in clock frequency will cause a different ETU,which itself will cause mistake in receiving correct data. AM I true ?

[Carlos_Mendoza · Accepted solution]

Hi Mahmoud,

You could use as reference the smartcard example that comes with the following software package:

https://www.lpcware.com/system/files/LPC11Uxx%20LPCXpresso%20Examples.zip 

Does your smart card allows the SCLK to be synchronously with the data and at the data bit rate? If yes you could better use the USART SCLK pin output.

In Smart card mode, OSInt is extended by FDINT. This extends the possible oversampling to 2048, as required to support ISO 7816-3.

Hope it helps!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[wowfoot]

smartcard example link is broken.
pls, another link?