diff --git a/armsrc/ticks.c b/armsrc/ticks.c index 0ce55e417..e9cbea219 100644 --- a/armsrc/ticks.c +++ b/armsrc/ticks.c @@ -117,47 +117,61 @@ uint32_t RAMFUNC GetCountUS(void) { 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_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 + | 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 = 0x01; // RC Compare value = 0x01, 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_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_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: 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 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 + } // 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