#include "proxmark3.h"
#include "util.h"
#include "string.h"
+#include "apps.h"
size_t nbytes(size_t nbits) {
return (nbits/8)+((nbits%8)>0);
// -------------------------------------------------------------------------
-// Mifare timer. Uses ssp_clk from FPGA
+// Timer for iso14443 commands. Uses ssp_clk from FPGA
// -------------------------------------------------------------------------
-void StartCountMifare()
+void StartCountSspClk()
{
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1) | (1 << AT91C_ID_TC2); // Enable Clock to all timers
AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_TIOA1 // XC0 Clock = TIOA1
AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK // TC1 Clock = MCK(48MHz)/2 = 24MHz
| AT91C_TC_CPCSTOP // Stop clock on RC compare
| AT91C_TC_EEVTEDG_RISING // Trigger on rising edge of Event
- | AT91C_TC_EEVT_TIOB // Event-Source: TIOB1 (= ssc_clk from FPGA = 13,56MHz / 16)
+ | AT91C_TC_EEVT_TIOB // Event-Source: TIOB1 (= ssp_clk from FPGA = 13,56MHz/16)
| AT91C_TC_ENETRG // Enable external trigger event
| AT91C_TC_WAVESEL_UP // Upmode without automatic trigger on RC compare
| AT91C_TC_WAVE // Waveform Mode
AT91C_BASE_TC1->TC_RC = 0x04; // RC Compare value = 0x04
// use TC0 to count TIOA1 pulses
- AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // disable TC0
+ AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // disable TC0
AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_XC0 // TC0 clock = XC0 clock = TIOA1
| AT91C_TC_WAVE // Waveform Mode
| AT91C_TC_WAVESEL_UP // just count
| AT91C_TC_WAVE // Waveform Mode
| AT91C_TC_WAVESEL_UP; // just count
-
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN; // enable TC0
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN; // enable TC1
AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN; // enable TC2
+
+ //
+ // synchronize the counter with the ssp_frame signal. Note: FPGA must be in any iso14446 mode, otherwise the frame signal would not be present
+ //
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME)); // wait for ssp_frame to go high (start of frame)
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME); // wait for ssp_frame to be low
+ // after the falling edge of ssp_frame, there is delay of 1/13,56MHz (73ns) until the next rising edge of ssp_clk. This are only a few
+ // processor cycles. We therefore may or may not be able to sync on this edge. Therefore better make sure that we miss it:
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high
+ // note: up to now two ssp_clk rising edges have passed since the rising edge of ssp_frame
+ // it is now safe to assert a sync signal. This sets all timers to 0 on next active clock edge
AT91C_BASE_TCB->TCB_BCR = 1; // assert Sync (set all timers to 0 on next active clock edge)
+ // at the next (3rd) ssp_clk rising edge, TC1 will be reset (and not generate a clock signal to TC0)
+ // at the next (4th) ssp_clk rising edge, TC0 (the low word of our counter) will be reset. From now on,
+ // whenever the last three bits of our counter go 0, we can be sure to be in the middle of a frame transfer.
+ // (just started with the transfer of the 4th Bit).
+ // The high word of the counter (TC2) will not reset until the low word (TC0) overflows. Therefore need to wait quite some time before
+ // we can use the counter.
+ while (AT91C_BASE_TC0->TC_CV < 0xFFF0);
}
-uint32_t RAMFUNC GetCountMifare(){
+uint32_t RAMFUNC GetCountSspClk(){
uint32_t tmp_count;
tmp_count = (AT91C_BASE_TC2->TC_CV << 16) | AT91C_BASE_TC0->TC_CV;
- if ((tmp_count & 0xffff) == 0) { //small chance that we may have missed an increment in TC2
+ if ((tmp_count & 0x0000ffff) == 0) { //small chance that we may have missed an increment in TC2
return (AT91C_BASE_TC2->TC_CV << 16);
}
else {
return tmp_count;
}
}
+
+