if ( len % 16 == 0 ) {
for(; p-buf < len; p += 16)
- Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+ Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
name,
p-buf,
len,
}
else {
for(; p-buf < len; p += 8)
- Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x", name, p-buf, len, p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
+ Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x", name, p-buf, len, p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
}
}
size_t nbytes(size_t nbits) {
- return (nbits/8)+((nbits%8)>0);
+ return (nbits >> 3)+((nbits % 8) > 0);
}
uint32_t SwapBits(uint32_t value, int nrbits) {
// RotateLeft - Ultralight, Desfire
void rol(uint8_t *data, const size_t len){
- uint8_t first = data[0];
- for (size_t i = 0; i < len-1; i++) {
- data[i] = data[i+1];
- }
- data[len-1] = first;
+ uint8_t first = data[0];
+ for (size_t i = 0; i < len-1; i++) {
+ data[i] = data[i+1];
+ }
+ data[len-1] = first;
}
void lsl (uint8_t *data, size_t len) {
- for (size_t n = 0; n < len - 1; n++) {
- data[n] = (data[n] << 1) | (data[n+1] >> 7);
- }
- data[len - 1] <<= 1;
-}
-
-int32_t le24toh (uint8_t data[3])
-{
- return (data[2] << 16) | (data[1] << 8) | data[0];
+ for (size_t n = 0; n < len - 1; n++) {
+ data[n] = (data[n] << 1) | (data[n+1] >> 7);
+ }
+ data[len - 1] <<= 1;
}
void LEDsoff()
LED_D_OFF();
}
+void LEDson()
+{
+ LED_A_ON();
+ LED_B_ON();
+ LED_C_ON();
+ LED_D_ON();
+}
+
+void LEDsinvert()
+{
+ LED_A_INV();
+ LED_B_INV();
+ LED_C_INV();
+ LED_D_INV();
+}
+
// LEDs: R(C) O(A) G(B) -- R(D) [1, 2, 4 and 8]
void LED(int led, int ms)
{
// not clicked, or held down (for ms || 1sec)
// In general, don't use this function unless you expect a
// double click, otherwise it will waste 500ms -- use BUTTON_HELD instead
-int BUTTON_CLICKED(int ms)
-{
+int BUTTON_CLICKED(int ms) {
// Up to 500ms in between clicks to mean a double click
int ticks = (48000 * (ms ? ms : 1000)) >> 10;
}
// Determine if a button is held down
-int BUTTON_HELD(int ms)
-{
+int BUTTON_HELD(int ms) {
// If button is held for one second
int ticks = (48000 * (ms ? ms : 1000)) >> 10;
uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR;
- for(;;)
- {
+ for(;;) {
uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR;
// As soon as our button let go, we didn't hold long enough
return BUTTON_SINGLE_CLICK;
// Have we waited the full second?
- else
- if (now == (uint16_t)(start + ticks))
+ else if (now == (uint16_t)(start + ticks))
return BUTTON_HOLD;
WDT_HIT();
// attempt at high resolution microsecond timer
// beware: timer counts in 21.3uS increments (1024/48Mhz)
-void SpinDelayUs(int us)
-{
+void SpinDelayUs(int us) {
int ticks = (48*us) >> 10;
// Borrow a PWM unit for my real-time clock
}
}
-void SpinDelay(int ms)
-{
+void SpinDelay(int ms) {
// convert to uS and call microsecond delay function
SpinDelayUs(ms*1000);
}
dst[0] = 0;
strncat(dst, prefix, len-1);
if(v->magic != VERSION_INFORMATION_MAGIC) {
- strncat(dst, "Missing/Invalid version information", len - strlen(dst) - 1);
+ strncat(dst, "Missing/Invalid version information\n", len - strlen(dst) - 1);
return;
}
if(v->versionversion != 1) {
- strncat(dst, "Version information not understood", len - strlen(dst) - 1);
+ strncat(dst, "Version information not understood\n", len - strlen(dst) - 1);
return;
}
if(!v->present) {
- strncat(dst, "Version information not available", len - strlen(dst) - 1);
+ strncat(dst, "Version information not available\n", len - strlen(dst) - 1);
return;
}
strncat(dst, " ", len - strlen(dst) - 1);
strncat(dst, v->buildtime, len - strlen(dst) - 1);
+ strncat(dst, "\n", len - strlen(dst) - 1);
}
+
// -------------------------------------------------------------------------
// timer lib
// -------------------------------------------------------------------------
// test procedure:
//
-// ti = GetTickCount();
-// SpinDelay(1000);
-// ti = GetTickCount() - ti;
-// Dbprintf("timer(1s): %d t=%d", ti, GetTickCount());
-
-void StartTickCount()
-{
-// must be 0x40, but on my cpu - included divider is optimal
-// 0x20 - 1 ms / bit
-// 0x40 - 2 ms / bit
-
- AT91C_BASE_RTTC->RTTC_RTMR = AT91C_RTTC_RTTRST + 0x001D; // was 0x003B
+// ti = GetTickCount();
+// SpinDelay(1000);
+// ti = GetTickCount() - ti;
+// Dbprintf("timer(1s): %d t=%d", ti, GetTickCount());
+
+void StartTickCount() {
+ // 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(){
+uint32_t RAMFUNC GetTickCount(void) {
return AT91C_BASE_RTTC->RTTC_RTVR;// was * 2;
}
+
// -------------------------------------------------------------------------
-// microseconds timer
+// microseconds timer
// -------------------------------------------------------------------------
-void StartCountUS()
-{
+void StartCountUS(void) {
AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
-// AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC1XC1S_TIOA0;
+// AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC1XC1S_TIOA0;
AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
// fast clock
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_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_BASE_TC1->TC_CCR = AT91C_TC_CLKEN;
AT91C_BASE_TCB->TCB_BCR = 1;
}
-uint32_t RAMFUNC GetCountUS(){
- return (AT91C_BASE_TC1->TC_CV * 0x8000) + ((AT91C_BASE_TC0->TC_CV / 15) * 10);
+
+uint32_t RAMFUNC GetCountUS(void) {
+ return (AT91C_BASE_TC1->TC_CV * 0x8000) + ((AT91C_BASE_TC0->TC_CV * 2) / 3); //was /15) * 10);
}
+
static uint32_t GlobalUsCounter = 0;
-uint32_t RAMFUNC GetDeltaCountUS(){
+uint32_t RAMFUNC GetDeltaCountUS(void) {
uint32_t g_cnt = GetCountUS();
uint32_t g_res = g_cnt - GlobalUsCounter;
GlobalUsCounter = g_cnt;
// -------------------------------------------------------------------------
-// Timer for iso14443 commands. Uses ssp_clk from FPGA
+// Timer for iso14443 commands. Uses ssp_clk from FPGA
// -------------------------------------------------------------------------
-void StartCountSspClk()
-{
+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
+ 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_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
+ | 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 ... 13,56MHz/4)
+ | 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 = 1; // RC Compare value = 1; pulse width to TC0
// 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
+ 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; // enable TC0
- AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN; // enable TC1
- AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN; // enable TC2
+ 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; // 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
+ // synchronize the counter with the ssp_frame signal. Note: FPGA must be in a FPGA mode with SSC transfer, otherwise SSC_FRAME and SSC_CLK signals 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
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME); // wait for ssp_frame to be low
+ 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_CLK)); // wait for ssp_clk to go high; 1st ssp_clk after start of frame
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low;
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 2nd ssp_clk after start of frame
+ if ((AT91C_BASE_SSC->SSC_RFMR & SSC_FRAME_MODE_BITS_IN_WORD(32)) == SSC_FRAME_MODE_BITS_IN_WORD(16)) { // 16bit frame
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low;
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 3rd ssp_clk after start of frame
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low;
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 4th ssp_clk after start of frame
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low;
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 5th ssp_clk after start of frame
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low;
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 6th ssp_clk after start of 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).
+ AT91C_BASE_TCB->TCB_BCR = 1; // assert Sync (set all timers to 0 on next active clock edge)
+ // at the next (3rd/7th) ssp_clk rising edge, TC1 will be reset (and not generate a clock signal to TC0)
+ // at the next (4th/8th) ssp_clk rising edge, TC0 (the low word of our counter) will be reset. From now on,
+ // whenever the last three/four bits of our counter go 0, we can be sure to be in the middle of a frame transfer.
+
// 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);
+ while (AT91C_BASE_TC0->TC_CV < 0xFFFF);
+ // Note: needs one more SSP_CLK cycle (1.18 us) until TC2 resets. Don't call GetCountSspClk() that soon.
}
-uint32_t RAMFUNC GetCountSspClk(){
- uint32_t tmp_count;
- 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);
- }
- else {
- return tmp_count;
- }
+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 GetCountSspClk(){
+ uint32_t hi, lo;
+
+ do {
+ hi = AT91C_BASE_TC2->TC_CV;
+ lo = AT91C_BASE_TC0->TC_CV;
+ } while (hi != AT91C_BASE_TC2->TC_CV);
+
+ return (hi << 16) | lo;
+}
+
+// -------------------------------------------------------------------------
+// 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 );
+}
+
+
+// Starts Clock and waits until its reset
+void ResetTicks(void){
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+ AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+ while (AT91C_BASE_TC0->TC_CV > 0);
+}
+
+
+void ResetTimer(AT91PS_TC timer){
+ timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+ while(timer->TC_CV > 0) ;
+}
+
+
+// stop clock
+void StopTicks(void){
+ AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+}
+
+
+static uint64_t next_random = 1;
+
+/* Generates a (non-cryptographically secure) 32-bit random number.
+ *
+ * We don't have an implementation of the "rand" function or a clock to seed it
+ * with, so we just call GetTickCount the first time to seed ourselves.
+ */
+uint32_t prand() {
+ if (next_random == 1) {
+ next_random = GetTickCount();
+ }
+
+ next_random = next_random * 6364136223846793005 + 1;
+ return (uint32_t)(next_random >> 32) % 0xffffffff;
+}