Diff: mbed-os/targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K64F/us_ticker.c

Revision:

0:8fdf9a60065b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K64F/us_ticker.c	Wed Oct 10 00:33:53 2018 +0000
@@ -0,0 +1,152 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2018 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stddef.h>
+#include "us_ticker_api.h"
+#include "PeripheralNames.h"
+#include "fsl_pit.h"
+#include "fsl_clock_config.h"
+
+const ticker_info_t* us_ticker_get_info()
+{
+    static const ticker_info_t info = {
+        1000000,    // 1 MHz
+             32     // 32 bit counter
+    };
+    return &info;
+}
+
+static bool us_ticker_inited = false;
+
+static void pit_isr(void)
+{
+    PIT_ClearStatusFlags(PIT, kPIT_Chnl_3, PIT_TFLG_TIF_MASK);
+    PIT_ClearStatusFlags(PIT, kPIT_Chnl_2, PIT_TFLG_TIF_MASK);
+    PIT_StopTimer(PIT, kPIT_Chnl_2);
+    PIT_StopTimer(PIT, kPIT_Chnl_3);
+
+    us_ticker_irq_handler();
+}
+
+/** Initialize the high frequency ticker
+ *
+ */
+void us_ticker_init(void)
+{
+    /* Common for ticker/timer. */
+    uint32_t busClock;
+    /* Structure to initialize PIT. */
+    pit_config_t pitConfig;
+
+    PIT_GetDefaultConfig(&pitConfig);
+    PIT_Init(PIT, &pitConfig);
+
+    busClock = CLOCK_GetFreq(kCLOCK_BusClk);
+
+    /* Let the timer to count if re-init. */
+    if (!us_ticker_inited) {
+
+        PIT_SetTimerPeriod(PIT, kPIT_Chnl_0, busClock / 1000000 - 1);
+        PIT_SetTimerPeriod(PIT, kPIT_Chnl_1, 0xFFFFFFFF);
+        PIT_SetTimerChainMode(PIT, kPIT_Chnl_1, true);
+        PIT_StartTimer(PIT, kPIT_Chnl_0);
+        PIT_StartTimer(PIT, kPIT_Chnl_1);
+    }
+
+    /* Configure interrupt generation counters and disable ticker interrupts. */
+    PIT_StopTimer(PIT, kPIT_Chnl_3);
+    PIT_StopTimer(PIT, kPIT_Chnl_2);
+    PIT_SetTimerPeriod(PIT, kPIT_Chnl_2, busClock / 1000000 - 1);
+    PIT_SetTimerChainMode(PIT, kPIT_Chnl_3, true);
+    PIT_ClearStatusFlags(PIT, kPIT_Chnl_3, PIT_TFLG_TIF_MASK);
+    NVIC_SetVector(PIT3_IRQn, (uint32_t) pit_isr);
+    NVIC_EnableIRQ(PIT3_IRQn);
+    PIT_DisableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable);
+
+    us_ticker_inited = true;
+}
+
+/** Read the current counter
+ *
+ * @return The current timer's counter value in ticks
+ */
+uint32_t us_ticker_read()
+{
+    return ~(PIT_GetCurrentTimerCount(PIT, kPIT_Chnl_1));
+}
+
+/** Disable us ticker interrupt
+ *
+ */
+void us_ticker_disable_interrupt(void)
+{
+    PIT_DisableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable);
+}
+
+/** Clear us ticker interrupt
+ *
+ */
+void us_ticker_clear_interrupt(void)
+{
+    PIT_ClearStatusFlags(PIT, kPIT_Chnl_3, PIT_TFLG_TIF_MASK);
+}
+
+/** Set interrupt for specified timestamp
+ *
+ * @param timestamp The time in ticks when interrupt should be generated
+ */
+void us_ticker_set_interrupt(timestamp_t timestamp)
+{
+    /* We get here absolute interrupt time which takes into account counter overflow.
+     * Since we use additional count-down timer to generate interrupt we need to calculate
+     * load value based on time-stamp.
+     */
+    const uint32_t now_ticks = us_ticker_read();
+    uint32_t delta_ticks =
+            timestamp >= now_ticks ? timestamp - now_ticks : (uint32_t)((uint64_t) timestamp + 0xFFFFFFFF - now_ticks);
+
+    if (delta_ticks == 0) {
+        /* The requested delay is less than the minimum resolution of this counter. */
+        delta_ticks = 1;
+    }
+
+    PIT_StopTimer(PIT, kPIT_Chnl_3);
+    PIT_StopTimer(PIT, kPIT_Chnl_2);
+    PIT_SetTimerPeriod(PIT, kPIT_Chnl_3, delta_ticks);
+    PIT_EnableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable);
+    PIT_StartTimer(PIT, kPIT_Chnl_3);
+    PIT_StartTimer(PIT, kPIT_Chnl_2);
+}
+
+/** Fire us ticker interrupt
+ *
+ */
+void us_ticker_fire_interrupt(void)
+{
+    NVIC_SetPendingIRQ(PIT3_IRQn);
+}
+
+void us_ticker_free(void)
+{
+    PIT_StartTimer(PIT, kPIT_Chnl_3);
+    PIT_StartTimer(PIT, kPIT_Chnl_2);
+    PIT_StartTimer(PIT, kPIT_Chnl_1);
+    PIT_StartTimer(PIT, kPIT_Chnl_0);
+
+    PIT_DisableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable);
+    NVIC_DisableIRQ(PIT3_IRQn);
+
+    us_ticker_inited = false;
+}