--- /dev/null
+#include <stdint.h>
+
+#include "serial_irq.h"
+#include "main_time.h"
+#include "main_emit.h"
+
+/*********************
+ * Signal generation *
+ *********************/
+
+// for 50 Mhz clock 50/1000 = 1/20 (PLL/2)
+
+// for 48 Mhz clock 48/1000 = 6/125 (FLL)
+// for 24 Mhz clock, 24/1000 = 3/125
+// for 12 Mhz clock, 12/1000 = 3/250
+// for 6 Mhz clock, 6/1000 = 3/500
+// for 3 Mhz clock, 3/1000 = 3/1000
+
+#define EMIT_PS 1
+
+//#if EMIT_PS == 0
+//#define EMIT_CLOCKS(nsec) ((uint16_t)((nsec) / 20))
+//#define EMIT_NSEC(clocks) ((uint16_t)((clocks) * 20))
+
+#if EMIT_PS == 0
+#define EMIT_CLOCKS(nsec) ((uint32_t)((nsec) * 6 / 125))
+#define EMIT_NSEC(clocks) ((uint32_t)((clocks) * 125 / 6))
+#elif EMIT_PS == 1
+#define EMIT_CLOCKS(nsec) ((uint32_t)((nsec) * 3 / 125))
+#define EMIT_NSEC(clocks) ((uint32_t)((clocks) * 125 / 3))
+#elif EMIT_PS == 2
+#define EMIT_CLOCKS(nsec) ((uint32_t)((nsec) * 3 / 250))
+#define EMIT_NSEC(clocks) ((uint32_t)((clocks) * 250 / 3))
+#elif EMIT_PS == 3
+#define EMIT_CLOCKS(nsec) ((uint32_t)((nsec) * 3 / 500))
+#define EMIT_NSEC(clocks) ((uint32_t)((clocks) * 500 / 3))
+#elif EMIT_PS == 4
+#define EMIT_CLOCKS(nsec) ((uint32_t)((nsec) * 3 / 1000))
+#define EMIT_NSEC(clocks) ((uint32_t)((clocks) * 1000 / 3))
+#endif
+
+static uint32_t *emit_pcr = 0; // transmit pin name
+
+static uint64_t emit_start = 0; // transmit start time (world time)
+static uint64_t emit_period = 0; // transmit period
+static uint64_t emit_due = 0; // next transmit (world time)
+
+static uint32_t emit_slack = 0; // how far ahead we need to schedule, in us
+static uint32_t emit_worst = 0; // worst-case latency in task table
+
+void emit_init(int alt, PinName pin, PinMode mode)
+{
+ // Find pin
+ emit_pcr = (uint32_t*)(PORTA_BASE + pin);
+
+ // Enable clocks
+ SIM->SCGC6 |= SIM_SCGC6_TPM1_MASK;
+ SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1);
+
+ // Reset PLL Source
+ //SIM->SOPT2 &= ~SIM_SOPT2_PLLFLLSEL_MASK;
+
+ // Debug print on SOPT2
+ // -- mbed may set PLLFLL when configuring UART0
+ // SOPT2: u0src=1 tpmsrc=1 USBSRC PLL/2 clkos=0 rtcos
+ sirq_printf("SOPT2: u0src=%d tpmsrc=%d %s %s clkos=%d %s\r\n",
+ (SIM->SOPT2 & SIM_SOPT2_UART0SRC_MASK) >> SIM_SOPT2_UART0SRC_SHIFT,
+ (SIM->SOPT2 & SIM_SOPT2_TPMSRC_MASK) >> SIM_SOPT2_TPMSRC_SHIFT,
+ (SIM->SOPT2 & SIM_SOPT2_UART0SRC_MASK) ? "USBSRC" : "usbsrc",
+ (SIM->SOPT2 & SIM_SOPT2_PLLFLLSEL_MASK) ? "PLL/2" : "FLL",
+ (SIM->SOPT2 & SIM_SOPT2_CLKOUTSEL_MASK) >> SIM_SOPT2_CLKOUTSEL_SHIFT,
+ (SIM->SOPT2 & SIM_SOPT2_RTCCLKOUTSEL_MASK) ? "RTCOS" : "rtcos");
+
+ // Set pin mode
+ emit_pcr[0] = PORT_PCR_ISF_MASK
+ | PORT_PCR_MUX(alt)
+ | mode;
+
+ // Setup Timer/PWM Module
+ TPM1->SC = TPM_SC_TOF_MASK;
+ TPM1->CNT = TPM_CNT_COUNT(0);
+ TPM1->MOD = TPM_MOD_MOD(0xFFFF);
+
+ TPM1->CONTROLS[0].CnSC = TPM_CnSC_CHF_MASK // clear flag
+ | TPM_CnSC_MSB_MASK // set output highon match,
+ | TPM_CnSC_ELSB_MASK // cleared on overflow
+ | TPM_CnSC_ELSA_MASK; // ..
+
+ TPM1->STATUS = TPM_STATUS_CH0F_MASK
+ | TPM_STATUS_TOF_MASK;
+
+ TPM1->CONF = TPM_CONF_CSOO_MASK;
+}
+
+void emit_enable(uint64_t start, uint64_t period)
+{
+ const int slack_clocks = 0x4000; // tune based on emit_worst
+
+ emit_start = start;
+ emit_period = period;
+ emit_due = start + period;
+
+ emit_slack = EMIT_NSEC(slack_clocks);
+
+ time_printf("emit scheduled", emit_due);
+}
+
+void emit_schedule(uint64_t when)
+{
+ uint64_t local = time_to_local(when) * 3 / 125;
+ uint32_t width = EMIT_CLOCKS(10000);
+
+ // Disable timer
+ TPM1->SC = TPM_SC_TOF_MASK;
+
+ __disable_irq();
+
+ uint64_t now = ((uint64_t)~PIT->LTMR64H << 32)
+ | ((uint64_t)~PIT->LTMR64L);
+ uint32_t delta = local - now;
+ uint32_t start = delta >> (EMIT_PS-1); // convert to clocks
+ uint32_t stop = start + width; // end time
+
+ // Set transmit time
+ TPM1->CONTROLS[0].CnV = start;
+ TPM1->MOD = TPM_MOD_MOD(stop);
+
+ // Start the timer
+ TPM1->SC = TPM_SC_TOF_MASK
+ | TPM_SC_PS(EMIT_PS)
+ | TPM_SC_CMOD(1);
+
+ __enable_irq();
+
+ // Test
+ //int64_t cnv = TPM1->CONTROLS[0].CnV;
+ //int64_t mod = TPM1->MOD;
+ //int64_t due = local - tdma_time();
+ //sirq_printf("%6d -- cnv=%04x mod=%04x due=%04x start=%04x\r\n",
+ // (int)(cnv - EMIT_CLOCKS(due)),
+ // (int)cnv, (int)mod,
+ // (int)EMIT_CLOCKS(due), EMIT_CLOCKS(start));
+
+ // Clock testing
+ //uint32_t test_tpm0 = TPM1->CNT;
+ //uint32_t test_pit0 = ~PIT->CHANNEL[0].CVAL;
+ //for (int i = 0; i < 100; i++)
+ // asm("nop");
+ //uint32_t test_tpm1 = TPM1->CNT;
+ //uint32_t test_pit1 = ~PIT->CHANNEL[0].CVAL;
+
+ //uint32_t test_tpm = test_tpm1 - test_tpm0;
+ //uint32_t test_pit = test_pit1 - test_pit0;
+ //sirq_printf("pit/tpm: %d - tpm=%08x/%08x=%d pit=%08x/%08x=%d\r\n",
+ // test_tpm - test_pit,
+ // test_tpm0, test_tpm1, test_tpm,
+ // test_pit0, test_pit1, test_pit);
+
+ // Debug output
+ //time_printf("emitting event", when);
+}
+
+void emit_transmit(uint64_t local, uint64_t world)
+{
+ static uint64_t prev = 0;
+
+ // Record how how much time we have to reschedule
+ if (prev && (local-prev) > emit_worst)
+ emit_worst = (local-prev);
+ prev = local;
+
+ // Schedule task if needed
+ if (emit_due && emit_period &&
+ world+emit_slack > emit_due) {
+ emit_schedule(emit_due);
+ emit_due += emit_period;
+ }
+}
+
projects / ~andy / csm213a-hw / blobdiff