sle_bbg.c File Reference

Bit banging driver to SLE4442. More...

#include <stdint.h>
#include <stdlib.h>
#include <avr/io.h>
#include <util/delay.h>
#include "sle_bbg.h"

Include dependency graph for sle_bbg.c:

Functions
void	ck_pulse (void)
void	set_io (const uint8_t io)
void	send_start (void)
void	send_stop (void)
uint8_t	read_byte (void)
void	send_byte (uint8_t byte)
void	send_rst (uint8_t *atr)
void	send_cmd (const uint8_t control, const uint8_t address, const uint8_t data)
uint8_t	processing (void)

Detailed Description

Bit banging driver to SLE4442.

Low level bit banging driver to read and write to Sle4442 card.

Function Documentation

ck_pulse()

void ck_pulse

(

void

)

Single clock pulse.

This function generates a single clock cycle onto the clock line.

processing()

uint8_t processing

(

void

)

Wait for the card to process the command.

Returns

the number of clock cycle waited.

Warning

if the card has problem and no bit comes from the IO line, the system hangs here.

read_byte()

uint8_t read_byte

(

void

)

Read a byte from IO line.

The function geneates 8 clock pulse cycle and on each of them a bit is read from the IO line.

Returns

The byte read.

Note

The IO line have to be already set to INPUT.

send_byte()

void send_byte

(

uint8_t

byte

)

Write a byte to the IO line.

The function write a byte a singe bit at a time, the bit is written on the 0 phase of the ck line, see datasheet.

Parameters

byte	the byte to be sent.

Note

the IO line should be already set to output.

send_cmd()

void send_cmd	(	const uint8_t	control,
		const uint8_t	address,
		const uint8_t	data
	)

Send a complete command sequence.

Parameters

control	the control byte.
address	the address byte.
data	the data byte.

Warning

After the command sequence, IO line is left in IN mode.

send_rst()

void send_rst

(

uint8_t *

atr

)

Send the reset (rst) sequence to the card.

See datasheet for details on the RST sequence.

Parameters

*atr	ptr to mem area where this function stores the 4 byte ATR returned after the RST.

Warning

The 4 byte ATR have to be already allocated.

send_start()

void send_start

(

void

)

Send the START sequence.

Warning

IO line will be set to OUT.

send_stop()

void send_stop

(

void

)

Send the STOP sequence.

Warning

IO line will be set to IN.

set_io()

void set_io

(

const uint8_t

io

)

Set's I/O line to one of: IN, OUT, 0 or 1.

IN: The port is in input, the subsequent call with: 0 - Disable internal pull-up resistor. 1 - Enable internal pull-up resistor.

OUT: The port in in output mode, the subsequent call with: 0 - Line is logic 0 (GND). 1 - Line is logic 1 (+5V).

Parameters

io	can be 0, 1, IN, OUT