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Refactor things around to make it easier to add a reader mode with code reuse

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henryk@ploetzli.ch 2009-11-05 11:13:46 +00:00
parent 4014b814fb
commit add16a6287
1 changed files with 59 additions and 34 deletions
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93
armsrc/legicrf.c
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@ -15,6 +15,30 @@ static struct legic_frame {
int bits;
uint16_t data;
} current_frame;
AT91PS_TC timer;
static void setup_timer(void)
{
/* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
* this it won't be terribly accurate but should be good enough.
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
timer = AT91C_BASE_TC1;
timer->TC_CCR = AT91C_TC_CLKDIS;
timer->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
/* At TIMER_CLOCK3 (MCK/32) */
#define RWD_TIME_1 150 /* RWD_TIME_PAUSE off, 80us on = 100us */
#define RWD_TIME_0 90 /* RWD_TIME_PAUSE off, 40us on = 60us */
#define RWD_TIME_PAUSE 30 /* 20us */
#define RWD_TIME_FUZZ 20 /* rather generous 13us, since the peak detector + hysteresis fuzz quite a bit */
#define TAG_TIME_BIT 150 /* 100us for every bit */
#define TAG_TIME_WAIT 490 /* time from RWD frame end to tag frame start, experimentally determined */
}
#define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
static const struct legic_frame queries[] = {
{7, 0x55}, /* 1010 101 */
@ -24,7 +48,10 @@ static const struct legic_frame responses[] = {
{6, 0x3b}, /* 1101 11 */
};
static void frame_send(uint16_t response, int bits)
/* Send a frame in tag mode, the FPGA must have been set up by
* LegicRfSimulate
*/
static void frame_send_tag(uint16_t response, int bits)
{
#if 0
/* Use the SSC to send a response. 8-bit transfers, LSBit first, 100us per bit */
@ -35,24 +62,25 @@ static void frame_send(uint16_t response, int bits)
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
/* Wait for the frame start */
while(AT91C_BASE_TC1->TC_CV < 490) ;
while(timer->TC_CV < TAG_TIME_WAIT) ;
int i;
for(i=0; i<bits; i++) {
int nextbit = AT91C_BASE_TC1->TC_CV + 150;
int nextbit = timer->TC_CV + TAG_TIME_BIT;
int bit = response & 1;
response = response >> 1;
if(bit)
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
else
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
while(AT91C_BASE_TC1->TC_CV < nextbit) ;
while(timer->TC_CV < nextbit) ;
}
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
#endif
}
static void frame_respond(struct legic_frame const * const f)
/* Figure out a response to a frame in tag mode */
static void frame_respond_tag(struct legic_frame const * const f)
{
LED_D_ON();
int i, r_size;
@ -67,7 +95,7 @@ static void frame_respond(struct legic_frame const * const f)
}
if(r_size != 0) {
frame_send(r_data, r_size);
frame_send_tag(r_data, r_size);
LED_A_ON();
} else {
LED_A_OFF();
@ -89,14 +117,15 @@ static int frame_is_empty(struct legic_frame const * const f)
return( f->bits <= 4 );
}
static void frame_handle(struct legic_frame const * const f)
/* Handle (whether to respond) a frame in tag mode */
static void frame_handle_tag(struct legic_frame const * const f)
{
if(f->bits == 6) {
/* Short path */
return;
}
if( !frame_is_empty(f) ) {
frame_respond(f);
frame_respond_tag(f);
}
}
@ -106,10 +135,16 @@ static void frame_clean(struct legic_frame * const f)
f->bits = 0;
}
static void emit(int bit)
enum emit_mode {
EMIT_RWD, /* Emit in tag simulation mode, e.g. the source is the RWD */
EMIT_TAG /* Emit in reader simulation mode, e.g. the source is the TAG */
};
static void emit(enum emit_mode mode, int bit)
{
if(bit == -1) {
frame_handle(&current_frame);
if(mode == EMIT_RWD) {
frame_handle_tag(&current_frame);
}
frame_clean(&current_frame);
} else if(bit == 0) {
frame_append_bit(&current_frame, 0);
@ -138,56 +173,46 @@ void LegicRfSimulate(void)
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
/* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
* this it won't be terribly accurate but should be good enough.
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
AT91C_BASE_TC1->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
int old_level = 0;
/* At TIMER_CLOCK3 (MCK/32) */
#define BIT_TIME_1 150
#define BIT_TIME_0 90
#define BIT_TIME_FUZZ 20
setup_timer();
int old_level = 0;
int active = 0;
while(!BUTTON_PRESS()) {
int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
int time = AT91C_BASE_TC1->TC_CV;
int time = timer->TC_CV;
if(level != old_level) {
if(level == 1) {
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
if(time > (BIT_TIME_1-BIT_TIME_FUZZ) && time < (BIT_TIME_1+BIT_TIME_FUZZ)) {
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
if(FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
/* 1 bit */
emit(1);
emit(EMIT_RWD, 1);
active = 1;
LED_B_ON();
} else if(time > (BIT_TIME_0-BIT_TIME_FUZZ) && time < (BIT_TIME_0+BIT_TIME_FUZZ)) {
} else if(FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
/* 0 bit */
emit(0);
emit(EMIT_RWD, 0);
active = 1;
LED_B_ON();
} else if(active) {
/* invalid */
emit(-1);
emit(EMIT_RWD, -1);
active = 0;
LED_B_OFF();
}
}
}
if(time >= (BIT_TIME_1+BIT_TIME_FUZZ) && active) {
if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
/* Frame end */
emit(-1);
emit(EMIT_RWD, -1);
active = 0;
LED_B_OFF();
}
if(time >= (20*BIT_TIME_1) && (AT91C_BASE_TC1->TC_SR & AT91C_TC_CLKSTA)) {
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA)) {
timer->TC_CCR = AT91C_TC_CLKDIS;
}