mifare card entegration via magstripe emulation to pic18f252 in C

[quillan]

Hello there. as a long time reader (but not a responder) i feel the urge to open this topic, as i'm stuck in a urgent topic.

i'm designing a mifare card reader system via pic18f252 (<- love this one)
card reader model is Gigatec MF7, which is a commonly found reader around.

the issue is not hardware, yet software. i already designed a weigand reader so i now some stuff about these things.

my pic18f252 got only one hard-uart port, which is already communicating an another device (to send the card info to a server via gprs etc).

the hardware i got has 3 interface options. Serial, weigand and Magstripe(clock&data). i cannot use serial, bec i dont have a second port on my pic (please dont say use another pic, i cannot change the hardware at this point). i cannot use weigand because i need a large range of card ID, which weigand cannot provide (says the guy i'm making the project, peh).

so i'm stuck with magstripe emulation. There isnt much info around the internet. those i found are exactly same as the little paper i got from the card readers box.


and here is my question. can anyone provide me software tips about how to read/process/decode/whatever the magstripe emulation protocol.
do i have to use clock or using only data pin is enough?

i'm 3 days away from my deadline, and i desperately need help 8-O

thanks and with my best regards,
Okan

 

[quillan]

ummmm, anyone, help?

 

[rmd]

Hope it´s not too late, but I have not read this post before.
Of course, you can always implemente a serial interface entirely in software, bit-banging the bytes thru a pair of pins... Nothing very difficult, moreover, C compilers as CCS implement this kind of interfaces. In an application I wrote (and is running into access systems in streets) I have three serial interfaces on a 18F4620: gprs, mifare reader, serial2ethernet (this one is the chip's real uart). All of them working happily at 9600 bps
Regards