proxmark3/armsrc/ticks.c

//-----------------------------------------------------------------------------
// Jonathan Westhues, Sept 2005
// Iceman, Sept 2016
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Timers, Clocks functions used in LF or Legic where you would need detailed time.
//-----------------------------------------------------------------------------
#include "ticks.h"
// attempt at high resolution microsecond timer
// beware: timer counts in 21.3uS increments (1024/48Mhz)
void SpinDelayUs(int us) {
	int ticks = (48 * us) >> 10;

	// Borrow a PWM unit for my real-time clock
	AT91C_BASE_PWMC->PWMC_ENA = PWM_CHANNEL(0);
	
	// 48 MHz / 1024 gives 46.875 kHz
	AT91C_BASE_PWMC_CH0->PWMC_CMR = PWM_CH_MODE_PRESCALER(10);		// Channel Mode Register
	AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0;							// Channel Duty Cycle Register
	AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff;						// Channel Period Register

	uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR;

	for(;;) {
		uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR;
		if (now == (uint16_t)(start + ticks))
			return;

		WDT_HIT();
	}
}

void SpinDelay(int ms) {
  // convert to uS and call microsecond delay function
	SpinDelayUs(ms*1000);
}
//  -------------------------------------------------------------------------
//  timer lib
//  -------------------------------------------------------------------------
//  test procedure:
//
//	ti = GetTickCount();
//	SpinDelay(1000);
//	ti = GetTickCount() - ti;
//	Dbprintf("timer(1s): %d t=%d", ti, GetTickCount());
void StartTickCount(void) {
	// This timer is based on the slow clock. The slow clock frequency is between 22kHz and 40kHz.
	// We can determine the actual slow clock frequency by looking at the Main Clock Frequency Register.
    uint16_t mainf = AT91C_BASE_PMC->PMC_MCFR & 0xffff;		// = 16 * main clock frequency (16MHz) / slow clock frequency
	// set RealTimeCounter divider to count at 1kHz:
	AT91C_BASE_RTTC->RTTC_RTMR = AT91C_RTTC_RTTRST | ((256000 + (mainf/2)) / mainf);
	// note: worst case precision is approx 2.5%
}

/*
* Get the current count.
*/
uint32_t RAMFUNC GetTickCount(void){
	return AT91C_BASE_RTTC->RTTC_RTVR;// was * 2;
}

//  -------------------------------------------------------------------------
//  microseconds timer 
//  -------------------------------------------------------------------------
void StartCountUS(void) {
	AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1);
	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;

	// fast clock
	// tick=1.5mks
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz) / 32 
								AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_ACPA_CLEAR |
								AT91C_TC_ACPC_SET | AT91C_TC_ASWTRG_SET;
	AT91C_BASE_TC0->TC_RA = 1;
	AT91C_BASE_TC0->TC_RC = 0xBFFF + 1; // 0xC000
	
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // timer disable  
	AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // from timer 0
	
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
	AT91C_BASE_TCB->TCB_BCR = 1;
	
	while (AT91C_BASE_TC1->TC_CV > 0);
}

uint32_t RAMFUNC GetCountUS(void){
	//return (AT91C_BASE_TC1->TC_CV * 0x8000) + ((AT91C_BASE_TC0->TC_CV / 15) * 10);
	//  By suggestion from PwPiwi, http://www.proxmark.org/forum/viewtopic.php?pid=17548#p17548
	return ((uint32_t)AT91C_BASE_TC1->TC_CV) * 0x8000 + (((uint32_t)AT91C_BASE_TC0->TC_CV) * 2) / 3;
}

//  -------------------------------------------------------------------------
//  Timer for iso14443 commands. Uses ssp_clk from FPGA 
//  -------------------------------------------------------------------------
void StartCountSspClk(void) {
	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_TCB_TC1XC1S_NONE 		// XC1 Clock = none
							| AT91C_TCB_TC2XC2S_TIOA0;		// XC2 Clock = TIOA0

	// configure TC1 to create a short pulse on TIOA1 when a rising edge on TIOB1 (= ssp_clk from FPGA) occurs:
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; 				// disable TC1
	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 (= 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_TC_AEEVT_SET 			// Set TIOA1 on external event
							| AT91C_TC_ACPC_CLEAR; 			// Clear TIOA1 on RC Compare
	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_CMR = AT91C_TC_CLKS_XC0	 			// TC0 clock = XC0 clock = TIOA1
							| AT91C_TC_WAVE 				// Waveform Mode
							| AT91C_TC_WAVESEL_UP	 		// just count
							| AT91C_TC_ACPA_CLEAR 			// Clear TIOA0 on RA Compare
							| AT91C_TC_ACPC_SET; 			// Set TIOA0 on RC Compare
	AT91C_BASE_TC0->TC_RA = 1;								// RA Compare value = 1; pulse width to TC2
	AT91C_BASE_TC0->TC_RC = 0; 								// RC Compare value = 0; increment TC2 on overflow

	// use TC2 to count TIOA0 pulses (giving us a 32bit counter (TC0/TC2) clocked by ssp_clk)
	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKDIS; 				// disable TC2  
	AT91C_BASE_TC2->TC_CMR = AT91C_TC_CLKS_XC2	 			// TC2 clock = XC2 clock = TIOA0
							| AT91C_TC_WAVE 				// Waveform Mode
							| AT91C_TC_WAVESEL_UP;	 		// just count

	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;				// enable and reset TC0
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;				// enable and reset TC1
	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;				// enable and reset TC2

	// synchronize the counter with the ssp_frame signal. 
	// Note: FPGA must be in any iso14443 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
	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_TC2->TC_CV > 0);
}
void ResetSspClk(void) {	
	//enable clock of timer and software trigger
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
	while (AT91C_BASE_TC2->TC_CV > 0);	
}
uint32_t RAMFUNC GetCountSspClk(void) {
	uint32_t tmp_count = (AT91C_BASE_TC2->TC_CV << 16) | AT91C_BASE_TC0->TC_CV;
	if ((tmp_count & 0x0000ffff) == 0)  //small chance that we may have missed an increment in TC2
		return (AT91C_BASE_TC2->TC_CV << 16);
	return tmp_count;
}

//  -------------------------------------------------------------------------
//  Timer for bitbanging, or LF stuff when you need a very precis timer
//  1us = 1.5ticks
//  -------------------------------------------------------------------------
void StartTicks(void){
	// initialization of the timer
	AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1);
	AT91C_BASE_TCB->TCB_BMR   = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;

	// disable TC0 and TC1 for re-configuration
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;

	// first configure TC1 (higher, 0xFFFF0000) 16 bit counter
	AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // just connect to TIOA0 from TC0
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // re-enable timer and wait for TC0

	// second configure TC0 (lower, 0x0000FFFF) 16 bit counter
	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz) / 32 
	                         AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO |
	                         AT91C_TC_ACPA_CLEAR | // RA comperator clears TIOA (carry bit)
	                         AT91C_TC_ACPC_SET |   // RC comperator sets TIOA (carry bit)
	                         AT91C_TC_ASWTRG_SET;  // SWTriger sets TIOA (carry bit)
	AT91C_BASE_TC0->TC_RC  = 0; // set TIOA (carry bit) on overflow, return to zero
	AT91C_BASE_TC0->TC_RA  = 1; // clear carry bit on next clock cycle
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // reset and re-enable timer

	// synchronized startup procedure
	while (AT91C_BASE_TC0->TC_CV > 0); // wait until TC0 returned to zero
	while (AT91C_BASE_TC0->TC_CV < 2); // and has started (TC_CV > TC_RA, now TC1 is cleared)

	// return to zero
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
	while (AT91C_BASE_TC0->TC_CV > 0);
}

uint32_t GetTicks(void) {
	uint32_t hi, lo;

	do {
		hi = AT91C_BASE_TC1->TC_CV;
		lo = AT91C_BASE_TC0->TC_CV;
	} while(hi != AT91C_BASE_TC1->TC_CV);

	return (hi << 16) | lo;
}

// Wait - Spindelay in ticks.
// if called with a high number, this will trigger the WDT...
void WaitTicks(uint32_t ticks){
	if ( ticks == 0 ) return;
	ticks += GetTicks();
	while (GetTicks() < ticks);
}

// Wait / Spindelay in us (microseconds) 
// 1us = 1.5ticks.
void WaitUS(uint16_t us){
	WaitTicks( (uint32_t)us * 3/2 );
}
void WaitMS(uint16_t ms){
	WaitTicks( (uint32_t)ms * 1500 );
}

// stop clock
void StopTicks(void){
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;	
}