X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/32cfae439e0e2270638617fa09bf1026b0cf0e50..a0cc89b47902cf6f61e08fceda9ac78df85b012e:/armsrc/util.c diff --git a/armsrc/util.c b/armsrc/util.c index e6332a7b..1dd8dc75 100644 --- a/armsrc/util.c +++ b/armsrc/util.c @@ -1,289 +1,433 @@ -//----------------------------------------------------------------------------- -// Utility functions used in many places, not specific to any piece of code. -// Jonathan Westhues, Sept 2005 -//----------------------------------------------------------------------------- -#include -#include "apps.h" - -void *memcpy(void *dest, const void *src, int len) -{ - BYTE *d = dest; - const BYTE *s = src; - while((len--) > 0) { - *d = *s; - d++; - s++; - } - return dest; -} - -void *memset(void *dest, int c, int len) -{ - BYTE *d = dest; - while((len--) > 0) { - *d = c; - d++; - } - return dest; -} - -int memcmp(const void *av, const void *bv, int len) -{ - const BYTE *a = av; - const BYTE *b = bv; - - while((len--) > 0) { - if(*a != *b) { - return *a - *b; - } - a++; - b++; - } - return 0; -} - -int strlen(char *str) -{ - int l = 0; - while(*str) { - l++; - str++; - } - return l; -} - -char* strncat(char *dest, const char *src, unsigned int n) -{ - unsigned int dest_len = strlen(dest); - unsigned int i; - - for (i = 0 ; i < n && src[i] != '\0' ; i++) - dest[dest_len + i] = src[i]; - dest[dest_len + i] = '\0'; - - return dest; -} - -void num_to_bytes(uint64_t n, size_t len, byte_t* dest) -{ - while (len--) { - dest[len] = (byte_t) n; - n >>= 8; - } -} - -uint64_t bytes_to_num(byte_t* src, size_t len) -{ - uint64_t num = 0; - while (len--) - { - num = (num << 8) | (*src); - src++; - } - return num; -} - -void LEDsoff() -{ - LED_A_OFF(); - LED_B_OFF(); - LED_C_OFF(); - LED_D_OFF(); -} - -// LEDs: R(C) O(A) G(B) -- R(D) [1, 2, 4 and 8] -void LED(int led, int ms) -{ - if (led & LED_RED) - LED_C_ON(); - if (led & LED_ORANGE) - LED_A_ON(); - if (led & LED_GREEN) - LED_B_ON(); - if (led & LED_RED2) - LED_D_ON(); - - if (!ms) - return; - - SpinDelay(ms); - - if (led & LED_RED) - LED_C_OFF(); - if (led & LED_ORANGE) - LED_A_OFF(); - if (led & LED_GREEN) - LED_B_OFF(); - if (led & LED_RED2) - LED_D_OFF(); -} - - -// Determine if a button is double clicked, single clicked, -// 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) -{ - // Up to 500ms in between clicks to mean a double click - int ticks = (48000 * (ms ? ms : 1000)) >> 10; - - // If we're not even pressed, forget about it! - if (!BUTTON_PRESS()) - return BUTTON_NO_CLICK; - - // 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); - AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; - AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - - int letoff = 0; - for(;;) - { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - - // We haven't let off the button yet - if (!letoff) - { - // We just let it off! - if (!BUTTON_PRESS()) - { - letoff = 1; - - // reset our timer for 500ms - start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - ticks = (48000 * (500)) >> 10; - } - - // Still haven't let it off - else - // Have we held down a full second? - if (now == (WORD)(start + ticks)) - return BUTTON_HOLD; - } - - // We already let off, did we click again? - else - // Sweet, double click! - if (BUTTON_PRESS()) - return BUTTON_DOUBLE_CLICK; - - // Have we ran out of time to double click? - else - if (now == (WORD)(start + ticks)) - // At least we did a single click - return BUTTON_SINGLE_CLICK; - - WDT_HIT(); - } - - // We should never get here - return BUTTON_ERROR; -} - -// Determine if a button is held down -int BUTTON_HELD(int ms) -{ - // If button is held for one second - int ticks = (48000 * (ms ? ms : 1000)) >> 10; - - // If we're not even pressed, forget about it! - if (!BUTTON_PRESS()) - return BUTTON_NO_CLICK; - - // 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); - AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; - AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - - for(;;) - { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - - // As soon as our button let go, we didn't hold long enough - if (!BUTTON_PRESS()) - return BUTTON_SINGLE_CLICK; - - // Have we waited the full second? - else - if (now == (WORD)(start + ticks)) - return BUTTON_HOLD; - - WDT_HIT(); - } - - // We should never get here - return BUTTON_ERROR; -} - -// 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); - AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; - AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - - for(;;) { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - if (now == (WORD)(start + ticks)) - return; - - WDT_HIT(); - } -} - -void SpinDelay(int ms) -{ - // convert to uS and call microsecond delay function - SpinDelayUs(ms*1000); -} - -/* Similar to FpgaGatherVersion this formats stored version information - * into a string representation. It takes a pointer to the struct version_information, - * verifies the magic properties, then stores a formatted string, prefixed by - * prefix in dst. - */ -void FormatVersionInformation(char *dst, int len, const char *prefix, void *version_information) -{ - struct version_information *v = (struct version_information*)version_information; - dst[0] = 0; - strncat(dst, prefix, len); - if(v->magic != VERSION_INFORMATION_MAGIC) { - strncat(dst, "Missing/Invalid version information", len); - return; - } - if(v->versionversion != 1) { - strncat(dst, "Version information not understood", len); - return; - } - if(!v->present) { - strncat(dst, "Version information not available", len); - return; - } - - strncat(dst, v->svnversion, len); - if(v->clean == 0) { - strncat(dst, "-unclean", len); - } else if(v->clean == 2) { - strncat(dst, "-suspect", len); - } - - strncat(dst, " ", len); - strncat(dst, v->buildtime, len); -} +//----------------------------------------------------------------------------- +// Jonathan Westhues, Sept 2005 +// +// 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. +//----------------------------------------------------------------------------- +// Utility functions used in many places, not specific to any piece of code. +//----------------------------------------------------------------------------- + +#include "proxmark3.h" +#include "util.h" +#include "string.h" +#include "apps.h" +#include "BigBuf.h" + + + +void print_result(char *name, uint8_t *buf, size_t len) { + uint8_t *p = buf; + + 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", + name, + p-buf, + len, + p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15] + ); + } + 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]); + } +} + +size_t nbytes(size_t nbits) { + return (nbits >> 3)+((nbits % 8) > 0); +} + +uint32_t SwapBits(uint32_t value, int nrbits) { + int i; + uint32_t newvalue = 0; + for(i = 0; i < nrbits; i++) { + newvalue ^= ((value >> i) & 1) << (nrbits - 1 - i); + } + return newvalue; +} + +void num_to_bytes(uint64_t n, size_t len, uint8_t* dest) +{ + while (len--) { + dest[len] = (uint8_t) n; + n >>= 8; + } +} + +uint64_t bytes_to_num(uint8_t* src, size_t len) +{ + uint64_t num = 0; + while (len--) + { + num = (num << 8) | (*src); + src++; + } + return num; +} + +// 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; +} +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]; +} + +void LEDsoff() +{ + LED_A_OFF(); + LED_B_OFF(); + LED_C_OFF(); + LED_D_OFF(); +} + +// LEDs: R(C) O(A) G(B) -- R(D) [1, 2, 4 and 8] +void LED(int led, int ms) +{ + if (led & LED_RED) + LED_C_ON(); + if (led & LED_ORANGE) + LED_A_ON(); + if (led & LED_GREEN) + LED_B_ON(); + if (led & LED_RED2) + LED_D_ON(); + + if (!ms) + return; + + SpinDelay(ms); + + if (led & LED_RED) + LED_C_OFF(); + if (led & LED_ORANGE) + LED_A_OFF(); + if (led & LED_GREEN) + LED_B_OFF(); + if (led & LED_RED2) + LED_D_OFF(); +} + + +// Determine if a button is double clicked, single clicked, +// 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) +{ + // Up to 500ms in between clicks to mean a double click + int ticks = (48000 * (ms ? ms : 1000)) >> 10; + + // If we're not even pressed, forget about it! + if (!BUTTON_PRESS()) + return BUTTON_NO_CLICK; + + // 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); + AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; + AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; + + uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + + int letoff = 0; + for(;;) + { + uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + + // We haven't let off the button yet + if (!letoff) + { + // We just let it off! + if (!BUTTON_PRESS()) + { + letoff = 1; + + // reset our timer for 500ms + start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + ticks = (48000 * (500)) >> 10; + } + + // Still haven't let it off + else + // Have we held down a full second? + if (now == (uint16_t)(start + ticks)) + return BUTTON_HOLD; + } + + // We already let off, did we click again? + else + // Sweet, double click! + if (BUTTON_PRESS()) + return BUTTON_DOUBLE_CLICK; + + // Have we ran out of time to double click? + else + if (now == (uint16_t)(start + ticks)) + // At least we did a single click + return BUTTON_SINGLE_CLICK; + + WDT_HIT(); + } + + // We should never get here + return BUTTON_ERROR; +} + +// Determine if a button is held down +int BUTTON_HELD(int ms) +{ + // If button is held for one second + int ticks = (48000 * (ms ? ms : 1000)) >> 10; + + // If we're not even pressed, forget about it! + if (!BUTTON_PRESS()) + return BUTTON_NO_CLICK; + + // 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); + AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; + AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; + + uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + + for(;;) + { + uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + + // As soon as our button let go, we didn't hold long enough + if (!BUTTON_PRESS()) + return BUTTON_SINGLE_CLICK; + + // Have we waited the full second? + else + if (now == (uint16_t)(start + ticks)) + return BUTTON_HOLD; + + WDT_HIT(); + } + + // We should never get here + return BUTTON_ERROR; +} + +// 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); + AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; + AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; + + 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); +} + +/* Similar to FpgaGatherVersion this formats stored version information + * into a string representation. It takes a pointer to the struct version_information, + * verifies the magic properties, then stores a formatted string, prefixed by + * prefix in dst. + */ +void FormatVersionInformation(char *dst, int len, const char *prefix, void *version_information) +{ + struct version_information *v = (struct version_information*)version_information; + dst[0] = 0; + strncat(dst, prefix, len-1); + if(v->magic != VERSION_INFORMATION_MAGIC) { + strncat(dst, "Missing/Invalid version information\n", len - strlen(dst) - 1); + return; + } + if(v->versionversion != 1) { + strncat(dst, "Version information not understood\n", len - strlen(dst) - 1); + return; + } + if(!v->present) { + strncat(dst, "Version information not available\n", len - strlen(dst) - 1); + return; + } + + strncat(dst, v->gitversion, len - strlen(dst) - 1); + if(v->clean == 0) { + strncat(dst, "-unclean", len - strlen(dst) - 1); + } else if(v->clean == 2) { + strncat(dst, "-suspect", len - strlen(dst) - 1); + } + + 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() +{ + // 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(){ + return AT91C_BASE_RTTC->RTTC_RTVR;// was * 2; +} + +// ------------------------------------------------------------------------- +// microseconds timer +// ------------------------------------------------------------------------- +void StartCountUS() +{ + 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_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE; + + // fast clock + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable + AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz)/32 -- tick=1.5mks + 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_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); +} + +static uint32_t GlobalUsCounter = 0; + +uint32_t RAMFUNC GetDeltaCountUS(){ + uint32_t g_cnt = GetCountUS(); + uint32_t g_res = g_cnt - GlobalUsCounter; + GlobalUsCounter = g_cnt; + return g_res; +} + + +// ------------------------------------------------------------------------- +// Timer for iso14443 commands. Uses ssp_clk from FPGA +// ------------------------------------------------------------------------- +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_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; // 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 + 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 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; + } +} +