sle_bbg.h File Reference

Bit banging driver to SLE4442. More...

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Macros
#define	SLE_PORT   PORTA
#define	SLE_PIN   PINA
#define	SLE_DDR   DDRA
#define	SLE_PRESENT   3
#define	SLE_RST   0
#define	SLE_CK   1
#define	SLE_IO   2
#define	OUT   2
#define	IN   3
#define	ck_delay()   _delay_us(25)
#define	ck_delay_front()   _delay_us(4)
#define	ck_delay_reset()   _delay_us(50)
#define	set_ck_1   SLE_PORT |= (1<<SLE_CK)
#define	set_ck_0   SLE_PORT &= ~(1<<SLE_CK)
#define	set_rst_1   SLE_PORT |= (1<<SLE_RST)
#define	set_rst_0   SLE_PORT &= ~(1<<SLE_RST)

Functions
void	ck_pulse (void)
void	set_io (const uint8_t io)
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.

Macro Definition Documentation

ck_delay

#define ck_delay

(

)

_delay_us(25)

The delay in usec for half of the wave.

example:

10Khz = 100usec.

20Khz = 50usec, half wave = 25 usec.

Remeber delay is only HALF of the freq. 20Khz total

ck_delay_front

#define ck_delay_front

(

)

_delay_us(4)

The MIN delay for a front phase between fronts of ck and/or rst and/or IO.

ck_delay_reset

#define ck_delay_reset

(

)

_delay_us(50)

delay reset = 1.

IN

#define IN   3

a simple macro to define IN as 3.

OUT

#define OUT   2

a simple macro to define OUT as 2.

set_ck_0

#define set_ck_0   SLE_PORT &= ~(1<<SLE_CK)

CK line to 0.

set_ck_1

#define set_ck_1   SLE_PORT |= (1<<SLE_CK)

CK line to 1.

set_rst_0

#define set_rst_0   SLE_PORT &= ~(1<<SLE_RST)

RST line to 0.

set_rst_1

#define set_rst_1   SLE_PORT |= (1<<SLE_RST)

RST line to 1.

SLE_CK

#define SLE_CK   1

clock pin of the card.

SLE_DDR

#define SLE_DDR   DDRA

The data direction register to handle the port's line direction.

SLE_IO

#define SLE_IO   2

I/O pin of the card.

SLE_PIN

#define SLE_PIN   PINA

The input port definition where the card is connected to.

SLE_PORT

#define SLE_PORT   PORTA

Port the card's reader is conneted to.

SLE_PRESENT

#define SLE_PRESENT   3

PIN connected to the present card switch.

SLE_RST

#define SLE_RST   0

PIN connected to the reset pin of the 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.

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