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Electronics => Electronics => Topic started by: airman00 on August 26, 2009, 12:56:38 PM

Title: Interfacing Axon with the SLE4442 SmartCard
Post by: airman00 on August 26, 2009, 12:56:38 PM

Hi all,
I'm playing around with some SLE4442 SmartCards, the same used here : http://hackaday.com/2008/11/25/how-to-read-a-fedex-kinkos-smart-card-sle4442/
Datasheet for SLE4442: http://www.smartcardsupply.com/PDF/DS_sle4432_42_0795.pdf

The interface is similar to I2C but not exactly the same. I need to send a clock pulse together with every bit I send to the SmartCard. I want to use the built in I2C ( or TWI as Atmel calls it) on the Axon to talk with the SmartCard. However, I2C bytes are 9 bits( one acknowledge bit), not 8 bits - I need 8 bits.
Very simply, I want to know how to use the built in I2C/TWI on the Axon to send clock pulses together with every bit , for bytes with a size of 8 bits

I also attached a part of the datasheet that deals with Resetting the SmartCard. It involves applying power to the Vcc Pin, Pulling the reset pin high, sending one clock pulse, pulling reset line low, and then sending out clock pulses to keep on receiving bits for a total of 32 bits or 8 bytes.

Thanks in Advance!

Title: Re: Interfacing Axon with the SLE4442 SmartCard
Post by: Webbot on August 26, 2009, 04:31:13 PM

Haven't had a chance to look at the datasheet in much detail but - it either IS or ISNT I2C. I fit isn't I2C then you can't use AVR I2C hardware - ie you will need to write your own code to toggle some I/O pins according to the timings in the spec.

Title: Re: Interfacing Axon with the SLE4442 SmartCard
Post by: Admin on August 26, 2009, 09:15:59 PM

Sounds like you can just bit-bang it as Webbot suggested.

Title: Re: Interfacing Axon with the SLE4442 SmartCard
Post by: airman00 on August 27, 2009, 06:22:50 AM

thanks for the replies

Yea I guess I'll have to bit bang it. Its not too bad now that I looked it over and understand it. I'll post documentation when I'm finished.