sysclk back to 168MHz, 10Mhz -> TIM2old-master

13 files changed, 300 insertions, 86 deletions

diff --git a/app/Makefile b/app/Makefile
index c0bbf4c..d4c56c5 100644
--- a/app/Makefile
+++ b/app/Makefile
@@ -25,7 +25,7 @@ PROG=msf
 V=1
 default: ${PROG}.elf
 
-CSRCS=led.c ticker.c ring.c usart.c stdio.c lwip_glue.c steth.c msf.c abs.c pll.c main.c time_fn.c ntp.c dcf77.c util.c stats.c gps.c hexdump.c bits.c  max7219.c  report.c
+CSRCS=led.c ticker.c ring.c usart.c stdio.c lwip_glue.c steth.c msf.c abs.c pll.c main.c time_fn.c ntp.c dcf77.c util.c stats.c gps.c hexdump.c bits.c  max7219.c  report.c sysclk.c
 HSRCS= events.h  gps.h  project.h  ring.h  steth.h  time_fn.h  ubx.h
 
 
diff --git a/app/abs.c b/app/abs.c
index 2ed8dd4..7a6b5d5 100644
--- a/app/abs.c
+++ b/app/abs.c
@@ -3,11 +3,14 @@
 
 static uint32_t high_tick;
 
+#if HW_CLOCK_LEN == 32
+
 #define QUARTER (1UL << 29)
 #define HALF (1UL << 30)
 #define THREE_QUARTERS (HALF+QUARTER)
 #define ONE (~(uint32_t)0)
 
+
 uint64_t abs_extend (uint32_t now)
 {
   static int m;
@@ -25,9 +28,7 @@ uint64_t abs_extend (uint32_t now)
       m = 1;
     }
 
-
   } else {
-
     if (now < HALF) {
       ret = high_tick;
       ret <<= 32;
@@ -44,6 +45,61 @@ uint64_t abs_extend (uint32_t now)
 
   return ret;
 }
+#elif HW_CLOCK_LEN == 31
+
+#define QUARTER (1UL << 28)
+#define HALF (1UL << 29)
+#define THREE_QUARTERS (HALF+QUARTER)
+#define ONE (0x7fffffff)
+
+
+uint64_t abs_extend (uint32_t now)
+{
+  static int m;
+  uint64_t ret;
+
+
+  if (!m) {
+    ret = high_tick;
+    ret <<= 31;
+    ret |= now;
+
+    if ((now > THREE_QUARTERS) && (now <= ONE)) {
+      high_tick++;
+      m = 1;
+    }
+
+  } else {
+    if (now < HALF) {
+      ret = high_tick;
+      ret <<= 31;
+      ret |= now;
+    } else {
+      ret = high_tick - 1;
+      ret <<= 31;
+      ret |= now;
+    }
+
+    if ((now > QUARTER) && (now < HALF))
+      m = 0;
+  }
+
+  return ret;
+}
+
+
+
+
+
+#else
+#error unknown hardware clock length
+#endif
+
+
+
+
+
+
 
 
 void abs_meh (void)
@@ -57,7 +113,7 @@ void abs_meh (void)
 
 uint64_t abs_get (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   return abs_extend (now);
 }
 
diff --git a/app/dcf77.c b/app/dcf77.c
index e55fcfc..fc2dcda 100644
--- a/app/dcf77.c
+++ b/app/dcf77.c
@@ -33,7 +33,7 @@ static char dcf77_info[40];
 
 void exti_t_isr (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   int v;
 
   v = !!gpio_get (T_PORT, T);
diff --git a/app/events.h b/app/events.h
index 8468851..550277d 100644
--- a/app/events.h
+++ b/app/events.h
@@ -3,7 +3,7 @@
 
 typedef struct {
   uint32_t when;
-  int value;
+  uint32_t value;
 } Event;
 
 
diff --git a/app/gps.c b/app/gps.c
index 9d5a992..c3ac2d1 100644
--- a/app/gps.c
+++ b/app/gps.c
@@ -1,8 +1,11 @@
 #include "project.h"
 
-#define PPS (GPIO9)
+#define PPS (GPIO7)
 #define PPS_PORT GPIOC
 
+#define NRESET (GPIO8)
+#define NRESET_PORT GPIOC
+
 #define UBX_BUF_LEN 256
 
 #define TIMEOUT 4000
@@ -23,27 +26,28 @@ uint64_t gps_last_happy;
 static  char fix, fix2;
 static int32_t freq = 0;
 
-static const int fish[] = { 1, 2, 3, 4, 5, 6, 7 };
+//static const int fish[] = { 1, 2, 3, 4, 5, 6, 7 };
 
 static Event_ring gps_ring;
 
 static char gps_info[60];
 
-
 void exti9_5_isr (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   int v;
 
   v = !!gpio_get (PPS_PORT, PPS);
 
   nvic_disable_irq (NVIC_EXTI9_5_IRQ);
-  exti_reset_request (EXTI9);
+  exti_reset_request (EXTI7);
 
   gps_ring.events[gps_ring.tx_ptr].when = now;
   gps_ring.events[gps_ring.tx_ptr].value = v;
   gps_ring.tx_ptr = (gps_ring.tx_ptr + 1) & ERING_MASK;
 
+  if (v) sysclk_event();
+
   nvic_enable_irq (NVIC_EXTI9_5_IRQ);
 
 }
@@ -270,7 +274,7 @@ ubx_recv_utc (uint8_t *ptr, unsigned len)
 
     next_sec = gps_time;
 
-    now = SCS_DWT_CYCCNT;
+    now = HW_CLOCK_REG;
     abs = abs_extend (now);
 
     gps_last_happy = make_happy (abs, 180);
@@ -578,7 +582,7 @@ static void gps_pps_dispatch (void)
   uint32_t now;
   uint64_t abs;
   int v;
-  EPOCH e;
+  //EPOCH e;
   //UTC u;
 
   if (gps_ring.rx_ptr == gps_ring.tx_ptr) return;
@@ -601,7 +605,7 @@ static void gps_pps_dispatch (void)
   if (gps_happy > 30)
     pll_dispatch (gps_last_happy, abs, "GPS");
 
-  e = pll_decompose (abs);
+  //e = pll_decompose (abs);
 
 
   //u = time_epoch_to_utc (e);
@@ -957,12 +961,17 @@ gps_init (void)
 
   //  printf ("GPS ready\r\n");
   //  ubx_get_clock_stats();
+  //
+
+
+  SET (NRESET);
 
   MAP_INPUT (PPS);
+  MAP_OUTPUT_PP (NRESET);
 
-  exti_select_source (EXTI9, PPS_PORT);
-  exti_set_trigger (EXTI9, EXTI_TRIGGER_BOTH);
-  exti_enable_request (EXTI9);
+  exti_select_source (EXTI7, PPS_PORT);
+  exti_set_trigger (EXTI7, EXTI_TRIGGER_BOTH);
+  exti_enable_request (EXTI7);
   nvic_enable_irq (NVIC_EXTI9_5_IRQ);
 
   return 0;
@@ -1009,7 +1018,7 @@ void gps_dump_almanac (void)
 #if 1
 int gps_bs (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   uint64_t abs = abs_extend (now);
   EPOCH e = pll_decompose (abs);
   UTC u = time_epoch_to_utc (e);
diff --git a/app/gps_neo8.c b/app/gps_neo8.c
index ea5d984..9da5438 100644
--- a/app/gps_neo8.c
+++ b/app/gps_neo8.c
@@ -29,7 +29,7 @@ static char gps_info[60];
 
 void exti9_5_isr (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   int v;
 
   v = !!gpio_get (PPS_PORT, PPS);
@@ -266,7 +266,7 @@ ubx_recv_utc (uint8_t *ptr, unsigned len)
     gps_time = time_utc_to_epoch (u);
 
 
-    now = SCS_DWT_CYCCNT;
+    now = HW_CLOCK_REG;
     abs = abs_extend (now);
 
     gps_last_happy = make_happy (abs, 180);
@@ -1040,7 +1040,7 @@ void gps_dump_almanac(void)
 #if 0
 int gps_bs(void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   uint64_t abs = abs_extend (now);
   EPOCH e = pll_decompose (abs);
   UTC u = time_epoch_to_utc (e);
@@ -1103,7 +1103,7 @@ int gps_bs(void)
 
 int gps_bs(void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   uint64_t abs = abs_extend (now);
   EPOCH e = pll_decompose (abs);
   UTC u = time_epoch_to_utc (e);
diff --git a/app/main.c b/app/main.c
index 4793f78..e3e3f63 100644
--- a/app/main.c
+++ b/app/main.c
@@ -78,7 +78,7 @@ static void pd_set (uint32_t g, uint32_t b)
 }
 
 
-static void pd(void)
+static void pd (void)
 {
   pd_port (GPIOA);
   pd_port (GPIOB);
@@ -138,6 +138,7 @@ static const clock_scale_t hse_10mhz_3v3_168 = {
   .apb2_frequency = 84000000,
 };
 
+#if 0
 static const clock_scale_t hse_10mhz_3v3_120 = {
   /* 120 */
   .pllm = 10,
@@ -194,82 +195,200 @@ static const clock_scale_t hse_10mhz_3v3_10 = {
   .ppre1 = RCC_CFGR_PPRE_DIV_NONE,
   .ppre2 = RCC_CFGR_PPRE_DIV_NONE,
   .flash_config = FLASH_ACR_ICE | FLASH_ACR_DCE | FLASH_ACR_LATENCY_0WS,
-//  .ahb_frequency  = 10000000,
+  //  .ahb_frequency  = 10000000,
   .apb1_frequency = 10000000,
   .apb2_frequency = 10000000,
 };
 
+#endif
+
 /*
- * Erugh the STM32F4's PLL is shite, we need 
- * to drive the entire clock tree from the 10MHz 
- * input, we use the PLL only to drive the 48MHz 
- * clock tree. 
+ * Erugh the STM32F4's PLL is shite, we need
+ * to drive the entire clock tree from the 10MHz
+ * input, we use the PLL only to drive the 48MHz
+ * clock tree.
  *
- * So PTP, AHB, APB1, APB2 all are directly from 
- * the HSE input 
+ * So PTP, AHB, APB1, APB2 all are directly from
+ * the HSE input
  */
 
 
-void rcc_clock_setup_hse_3v3_no_pll(const clock_scale_t *clock)
+void rcc_clock_setup_hse_3v3_no_pll (const clock_scale_t *clock)
 {
-        /* Enable internal high-speed oscillator. */
-        rcc_osc_on(HSI);
-        rcc_wait_for_osc_ready(HSI);
-
-        /* Select HSI as SYSCLK source. */
-        rcc_set_sysclk_source(RCC_CFGR_SW_HSI);
-
-        /* Enable external high-speed oscillator 8MHz. */
-        rcc_osc_on(HSE);
-        rcc_wait_for_osc_ready(HSE);
-
-        /* Enable/disable high performance mode */
-        if (!clock->power_save) {
-                pwr_set_vos_scale(SCALE1);
-        } else {
-                pwr_set_vos_scale(SCALE2);
-        }
-
-        /*
-         * Set prescalers for AHB, ADC, ABP1, ABP2.
-         * Do this before touching the PLL (TODO: why?).
-         */
-        rcc_set_hpre(clock->hpre);
-        rcc_set_ppre1(clock->ppre1);
-        rcc_set_ppre2(clock->ppre2);
-
-        rcc_set_main_pll_hse(clock->pllm, clock->plln,
+  /* Enable internal high-speed oscillator. */
+  rcc_osc_on (HSI);
+  rcc_wait_for_osc_ready (HSI);
+
+  /* Select HSI as SYSCLK source. */
+  rcc_set_sysclk_source (RCC_CFGR_SW_HSI);
+
+  /* receive the 10MHz external oscillator */
+  rcc_osc_bypass_enable (HSE);
+  rcc_osc_on (HSE);
+  rcc_wait_for_osc_ready (HSE);
+
+  /* Enable/disable high performance mode */
+  if (!clock->power_save)
+    pwr_set_vos_scale (SCALE1);
+  else
+    pwr_set_vos_scale (SCALE2);
+
+  /*
+   * Set prescalers for AHB, ADC, ABP1, ABP2.
+   * Do this before touching the PLL (TODO: why?).
+   */
+  rcc_set_hpre (clock->hpre);
+  rcc_set_ppre1 (clock->ppre1);
+  rcc_set_ppre2 (clock->ppre2);
+
+  rcc_set_main_pll_hse (clock->pllm, clock->plln,
                         clock->pllp, clock->pllq);
 
-        /* Enable PLL oscillator and wait for it to stabilize. */
-        rcc_osc_on(PLL);
-        rcc_wait_for_osc_ready(PLL);
+  /* Enable PLL oscillator and wait for it to stabilize. */
+  rcc_osc_on (PLL);
+  rcc_wait_for_osc_ready (PLL);
 
-        /* Configure flash settings. */
-        flash_set_ws(clock->flash_config);
+  /* Configure flash settings. */
+  flash_set_ws (clock->flash_config);
 
-        /* Select PLL as SYSCLK source. */
-        rcc_set_sysclk_source(RCC_CFGR_SW_HSE);
+  /* Select HSE as SYSCLK source. */
+  rcc_set_sysclk_source (RCC_CFGR_SW_HSE);
 
-        /* Wait for PLL clock to be selected. */
-        rcc_wait_for_sysclk_status(HSE);
+  /* Wait for HSE clock to be selected. */
+  rcc_wait_for_sysclk_status (HSE);
 
-        /* Set the peripheral clock frequencies used. */
-        rcc_apb1_frequency = clock->apb1_frequency;
-        rcc_apb2_frequency = clock->apb2_frequency;
+  /* Set the peripheral clock frequencies used. */
+  rcc_apb1_frequency = clock->apb1_frequency;
+  rcc_apb2_frequency = clock->apb2_frequency;
 
-        /* Disable internal high-speed oscillator. */
-        rcc_osc_off(HSI);
+  /* Disable internal high-speed oscillator. */
+  rcc_osc_off (HSI);
 }
 
+static void ptp_clock_start (void)
+{
+  /* Get the PTP clock running early */
+  ETH_PTPTSCR |= ETH_PTPTSCR_TSE;
+  ETH_PTPSSIR = 1;
 
-static void
-board_setup (void)
+  ETH_PTPTSCR &= ~ETH_PTPTSCR_TSFCU;
+  ETH_PTPTSCR &= ~ETH_PTPTSCR_TSSSR;
+
+  ETH_PTPTSHUR = 0;
+  ETH_PTPTSLUR = 0;
+
+  ETH_PTPTSCR |= ETH_PTPTSCR_TSSTI;
+}
+
+
+static void clock_setup (void)
 {
+  /*
+   * Caution, The PLL is somewhat rubbish, and causes all sorts of misery
+   * so sysclk isn't really a reference, if we use it, however not using it
+   * means sysclk is 10MHz which is too slow to do ntp and ptp, instead
+   * we route HSE out through MCO1 (as it's not necessarily LVTTL at the
+   * input) and connect that to TIM1_ETR
+   *
+   */
+
+  /* confiure HSE as input not oscillator */
   rcc_osc_bypass_enable (HSE);
+
+  /* turn off SSC */
   RCC_SSCGR = 0;
-//  rcc_clock_setup_hse_3v3 (&hse_10mhz_3v3_168);
-  rcc_clock_setup_hse_3v3_no_pll (&hse_10mhz_3v3_10);
+
+  /* Route HSE out through MCO1 (PA8) which we connect to TIM1_ETR (PE7)*/
+
+  RCC_CFGR &= ~ (RCC_CFGR_MCO1_PLL << RCC_CFGR_MCO1_SHIFT);
+  RCC_CFGR |= RCC_CFGR_MCO1_HSE << RCC_CFGR_MCO1_SHIFT;
+
+  RCC_CFGR &= ~ (RCC_CFGR_MCOPRE_DIV_5 << RCC_CFGR_MCO1PRE_SHIFT);
+  RCC_CFGR |= RCC_CFGR_MCOPRE_DIV_NONE << RCC_CFGR_MCO1PRE_SHIFT;
+
+  rcc_clock_setup_hse_3v3 (&hse_10mhz_3v3_168);
+  /* rcc_clock_setup_hse_3v3_no_pll (&hse_10mhz_3v3_10); */
+
+
+}
+#define REFCLK_OUT (GPIO8)
+#define REFCLK_OUT_PORT GPIOA
+
+#define REFCLK_IN (GPIO7)
+#define REFCLK_IN_PORT GPIOE
+
+static void timer_setup (void)
+{
+  MAP_INPUT (REFCLK_OUT);
+  MAP_INPUT (REFCLK_IN);
+  MAP_AF (REFCLK_OUT, GPIO_AF0);
+  MAP_AF (REFCLK_IN, GPIO_AF1);
+
+
+#if 0
+  /* Divide by 2 to trigger TIM2 */
+  timer_reset (TIM1);
+  timer_set_mode (TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
+  timer_set_master_mode (TIM1, TIM_CR2_MMS_UPDATE);
+  timer_set_period (TIM1, 1);
+  timer_slave_set_filter (TIM1, TIM_SMCR_ETF_OFF);
+  timer_slave_set_prescaler (TIM1, TIM_SMCR_ETPS_OFF);
+  TIM1_SMCR |= TIM_SMCR_ECE;
+  timer_enable_counter (TIM1);
+
+  timer_reset (TIM2);
+  timer_set_mode (TIM2, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
+  timer_slave_set_filter (TIM2, TIM_SMCR_ETF_OFF); /*no filter*/
+  timer_slave_set_prescaler (TIM2, TIM_SMCR_ETPS_OFF); /*no prescaler */
+  timer_slave_set_polarity (TIM2, TIM_ET_RISING); /*rising edge */
+  timer_slave_set_mode (TIM2, TIM_SMCR_SMS_ECM1); /*external clock mode 1*/
+  timer_slave_set_trigger (TIM2, TIM_SMCR_TS_ITR0); /*clock from timer 1*/
+  timer_enable_counter (TIM2);
+#endif
+
+
+
+  /*
+   * so TIM1 which I wired the 10MHz in to turns out to be only 16 bit
+   * so it's a chocolate teapot for this application
+   *
+   * after much faffing what works is the following, configure
+   * the TIM1_ETR to synchronously reset TIM1
+   * connect the TIM1_RESET line to the TIM1_TRGO line
+   * use TIM1_TRGO as TIM2_TRGI, and set TIM2 to upcount
+   * on each rising edge of TRGI
+   *
+   * there's a promising tim2 ETRF input on one of the unused jtag pins
+   * but that requires going up a ladder...
+   *
+   */
+
+
+  timer_reset (TIM1);
+  timer_set_mode (TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); /* meh */
+  timer_slave_set_filter (TIM1, TIM_SMCR_ETF_OFF); /* No filter */
+  timer_slave_set_prescaler (TIM1, TIM_SMCR_ETPS_OFF); /* no prescaler */
+  timer_slave_set_trigger (TIM1, TIM_SMCR_TS_ETRF); /* Trigger from ETR input */
+  timer_slave_set_mode (TIM1, TIM_SMCR_SMS_RM); /* trigger resets timer */
+  timer_set_master_mode (TIM1, TIM_CR2_MMS_RESET); /* output reset on TRGO */
+  timer_enable_counter (TIM1); /* go */
+
+  timer_reset (TIM2);
+  timer_set_mode (TIM2, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); /* count up with clock*/
+  timer_slave_set_filter (TIM2, TIM_SMCR_ETF_OFF); /*no filter*/
+  timer_slave_set_prescaler (TIM2, TIM_SMCR_ETPS_OFF); /*no prescaler */
+  timer_slave_set_polarity (TIM2, TIM_ET_RISING); /*rising edge */
+  timer_slave_set_mode (TIM2, TIM_SMCR_SMS_ECM1); /*external clock mode 1*/
+  timer_slave_set_trigger (TIM2, TIM_SMCR_TS_ITR0); /*clock from timer 1*/
+  timer_enable_counter (TIM2);
+
+
+}
+
+static void
+board_setup (void)
+{
+  clock_setup();
 
   rcc_periph_clock_enable (RCC_SYSCFG);
   rcc_periph_clock_enable (RCC_GPIOA);
@@ -285,6 +404,8 @@ board_setup (void)
   rcc_periph_clock_enable (RCC_ETHMACTX);
   rcc_periph_clock_enable (RCC_ETHMACRX);
   rcc_periph_clock_enable (RCC_ETHMACPTP);
+  rcc_periph_clock_enable (RCC_TIM1);
+  rcc_periph_clock_enable (RCC_TIM2);
 
   nvic_set_priority (NVIC_EXTI9_5_IRQ, 0x00);
   nvic_set_priority (NVIC_EXTI3_IRQ, 0x10);
@@ -294,6 +415,7 @@ board_setup (void)
   nvic_set_priority (NVIC_ETH_IRQ, 0x40);
   nvic_set_priority (NVIC_SYSTICK_IRQ, 0x50);
 
+
   //  nvic_enable_irq (NVIC_EXTI15_10_IRQ);
 }
 
@@ -303,6 +425,9 @@ system_init (void)
 {
 
   board_setup();
+
+  timer_setup();
+
   led_init();
   ticker_init();
 
@@ -316,6 +441,8 @@ system_init (void)
   printf ("STETH\r\n");
   steth_init();
 
+  ptp_clock_start();
+
   max7219_init (1);
 
   gps_init();
@@ -335,7 +462,7 @@ main (void)
 #if 0
 
   while (1) {
-    uint32_t now = SCS_DWT_CYCCNT;
+    uint32_t now = HW_CLOCK_REG;
     uint64_t abs =  abs_extend (now);
     EPOCH e = pll_decompose (abs);
     time_print_epoch ("TEST: ", e);
@@ -349,7 +476,7 @@ main (void)
   while (1) {
 #if 0
     {
-      uint32_t now = SCS_DWT_CYCCNT;
+      uint32_t now = HW_CLOCK_REG;
       uint64_t abs =  abs_extend (now);
       EPOCH e = pll_decompose (abs);
       time_print_epoch ("TEST: ", e);
@@ -362,8 +489,8 @@ main (void)
 
     msf_dispatch();
     dcf77_dispatch();
-
     gps_dispatch();
+    sysclk_dispatch();
     cmd_dispatch();
     dispatch_lwip();
 
diff --git a/app/max7219.c b/app/max7219.c
index fbba10d..bebfa50 100644
--- a/app/max7219.c
+++ b/app/max7219.c
@@ -103,7 +103,7 @@ void max7219_write (int d, int h, int m, int s)
 
 void max7219_dispatch (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   uint64_t abs =  abs_extend (now);
   EPOCH e = pll_decompose (abs);
   UTC u = time_epoch_to_utc (e);
diff --git a/app/msf.c b/app/msf.c
index 954e57f..9d8db3f 100644
--- a/app/msf.c
+++ b/app/msf.c
@@ -32,7 +32,7 @@ static EPOCH msf_time;
 
 void exti_t_isr (void)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   int v;
 
   v = !!gpio_get (T_PORT, T);
diff --git a/app/ntp.c b/app/ntp.c
index f8ca357..0bdda4d 100644
--- a/app/ntp.c
+++ b/app/ntp.c
@@ -69,7 +69,7 @@ static uint64_t ntp_ts (uint64_t v)
 
 static void ntp_rx (void *arg, struct udp_pcb *s, struct pbuf *p, struct ip_addr *src_addr, u16_t port)
 {
-  uint32_t now = SCS_DWT_CYCCNT;
+  uint32_t now = HW_CLOCK_REG;
   struct ip_addr dst_addr = *src_addr;
   ntp_packet_t pkt;
 
@@ -102,7 +102,7 @@ static void ntp_rx (void *arg, struct udp_pcb *s, struct pbuf *p, struct ip_addr
     pkt.receive_ts = ntp_ts (abs_extend (now));
     pkt.reference_ts = ntp_ts (pll_last_update);
 
-    now = SCS_DWT_CYCCNT;
+    now = HW_CLOCK_REG;
     pkt.transmit_ts = ntp_ts (abs_extend (now));
 
     memcpy (p->payload, &pkt, sizeof (ntp_packet_t));
diff --git a/app/project.h b/app/project.h
index 47eecb3..d060a81 100644
--- a/app/project.h
+++ b/app/project.h
@@ -15,6 +15,7 @@
 #include <libopencm3/stm32/adc.h>
 #include <libopencm3/stm32/exti.h>
 #include <libopencm3/stm32/pwr.h>
+#include <libopencm3/stm32/timer.h>
 #include <libopencm3/ethernet/mac_stm32fxx7.h>
 #include <libopencm3/ethernet/phy.h>
 #include <libopencm3/stm32/syscfg.h>
@@ -45,12 +46,26 @@
 
 #include "prototypes.h"
 
-#define HZ 10000000
+//#define HZ 10000000
+#define HZ   10000000
+
 //#define HZ 167999973
 //#define HZ 168000000
 //#define HZ 167968615
 //#define HZ 165925490
 //#define HZ 167996682
+//
+
+#if 0
+#define HW_CLOCK_REG SCS_DWT_CYCCNT
+#define HW_CLOCK_LEN 32
+#elif 0
+#define HW_CLOCK_REG ETH_PTPTSLR
+#define HW_CLOCK_LEN 31
+#else
+#define HW_CLOCK_REG TIM2_CNT
+#define HW_CLOCK_LEN 32
+#endif
 
 #define TRACE do { stdio_drain(); printf("%s:%d\r\n",__FUNCTION__,__LINE__); } while (0)
 
diff --git a/app/prototypes.h b/app/prototypes.h
index 667262b..8779f8d 100644
--- a/app/prototypes.h
+++ b/app/prototypes.h
@@ -117,3 +117,7 @@ extern void max7219_dispatch(void);
 extern void max7219_init(int on);
 /* report.c */
 extern void report_time(const char *src, EPOCH e, uint64_t abs, const char *info);
+/* sysclk.c */
+extern void sysclk_event(void);
+extern uint64_t sysclk_extend(uint32_t now);
+extern void sysclk_dispatch(void);
diff --git a/app/steth.c b/app/steth.c
index 7b23b3c..26429aa 100644
--- a/app/steth.c
+++ b/app/steth.c
@@ -215,6 +215,7 @@ static void my_eth_init (uint8_t phy, enum eth_clk clock)
 
 
 
+#if 0
 static void phy_set_ignore_address (void)
 {
   unsigned i;
@@ -241,7 +242,7 @@ static void phy_set_ignore_address (void)
 
   eth_smi_write (PHY1, 0x11, 0x8);
 }
-
+#endif
 
 static void eth_reset (void)
 {
@@ -423,7 +424,8 @@ void steth_slow_tick (void)
   if ((!phy_link_isup (PHY) || !an_happy) && running) {
 
     printf ("stopping nic\r\n");
-    eth_reset();
+    //eth_reset();
+    ETH_MACCR |= ETH_MACCR_RD;
 
     running = 0;
 
@@ -453,6 +455,7 @@ void steth_slow_tick (void)
     switch (phy_link_status (PHY)) {
     case LINK_HD_10M:
       TRACE;
+      break;
 
     case LINK_HD_100M:
       TRACE;