Merge pull request #1598 from haukepetersen/add_nrf_rtt

cpu/board: added RTT driver for NRF51822

boards/pca10000/include/periph_conf.h

@@ -15,12 +15,12 @@
  *
  * @author      Christian Kühling <kuehling@zedat.fu-berlin.de>
  * @author      Timo Ziegler <timo.ziegler@fu-berlin.de>
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
 #ifndef __PERIPH_CONF_H
 #define __PERIPH_CONF_H
 
-
 /**
  * @name Timer configuration
  * @{
@@ -53,6 +53,20 @@
 #define TIMER_2_IRQ         TIMER2_IRQn
 /** @} */
 
+/**
+ * @name Real time counter configuration
+ * @{
+ */
+#define RTT_NUMOF           (1U)
+#define RTT_IRQ_PRIO        1
+
+#define RTT_DEV             NRF_RTC0
+#define RTT_IRQ             RTC0_IRQn
+#define RTT_ISR             isr_rtc0
+#define RTT_MAX_VALUE       (0xffffff)
+#define RTT_FREQUENCY       (10)            /* in Hz */
+#define RTT_PRESCALER       (3275U)         /* run with 10 Hz */
+/** @} */
 
 /**
  * @name UART configuration

cpu/nrf51822/periph/rtt.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup     cpu_nrf51822
+ * @{
+ *
+ * @file        rtt.c
+ * @brief       Real-time timer driver implementation
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "cpu.h"
+#include "board.h"
+#include "sched.h"
+#include "thread.h"
+#include "periph_conf.h"
+#include "periph/rtt.h"
+
+/* guard file in case no RTC device was specified */
+#if RTT_NUMOF
+
+/*
+ * callback and argument for an active alarm
+ */
+static rtt_alarm_cb_t alarm_cb;
+static void *alarm_arg;
+
+void rtt_init(void)
+{
+    rtt_poweron();
+
+    /* configure interrupt */
+    NVIC_SetPriority(RTT_IRQ, RTT_IRQ_PRIO);
+    NVIC_EnableIRQ(RTT_IRQ);
+
+    /* set prescaler */
+    RTT_DEV->PRESCALER = RTT_PRESCALER;
+
+    /* enable the low-frequency clock */
+    NRF_CLOCK->TASKS_LFCLKSTART = 1;
+
+    /* start the actual RTT thing */
+    RTT_DEV->TASKS_START = 1;
+}
+
+uint32_t rtt_get_counter(void)
+{
+    return RTT_DEV->COUNTER;
+}
+
+void rtt_set_counter(uint32_t counter)
+{
+    /* not supported for the NRF51822? -> could not find out how to do this */
+}
+
+void rtt_set_alarm(uint32_t alarm, rtt_alarm_cb_t cb, void *arg)
+{
+    alarm_cb = cb;
+    alarm_arg = arg;
+    RTT_DEV->CC[0] = (alarm & RTT_MAX_VALUE);
+    RTT_DEV->INTENSET = RTC_INTENSET_COMPARE0_Msk;
+}
+
+uint32_t rtt_get_alarm(void)
+{
+    return RTT_DEV->CC[0];
+}
+
+void rtt_clear_alarm(void)
+{
+    RTT_DEV->INTENCLR = RTC_INTENSET_COMPARE0_Msk;
+}
+
+void rtt_poweron(void)
+{
+    RTT_DEV->POWER = 1;
+}
+
+void rtt_poweroff(void)
+{
+    RTT_DEV->POWER = 0;
+}
+
+__attribute__((naked)) void RTT_ISR(void)
+{
+    ISR_ENTER();
+    if (RTT_DEV->EVENTS_COMPARE[0] ==1) {
+        RTT_DEV->EVENTS_COMPARE[0] = 0;
+        RTT_DEV->INTENCLR = RTC_INTENSET_COMPARE0_Msk;
+        alarm_cb(alarm_arg);
+    }
+    if (sched_context_switch_request) {
+        thread_yield();
+    }
+    ISR_EXIT();
+}
+
+#endif /* RTT_NUMOF */

tests/periph_rtt/Makefile

@@ -0,0 +1,10 @@
+export APPLICATION = periph_rtt
+include ../Makefile.tests_common
+
+BOARD_BLACKLIST := chronos mbed_lpc1768 msb-430 msb-430h native qemu-i386 redbee-econotag telosb \
+                   wsn430-v1_3b wsn430-v1_4 z1
+# all listed boards: no periph_conf.h defined,
+
+DISABLE_MODULE += auto_init
+
+include $(RIOTBASE)/Makefile.include

tests/periph_rtt/README.md

@@ -0,0 +1,7 @@
+Expected result
+===============
+When everything works as expected, you should see a hello message popping up every 10 seconds.
+
+Background
+==========
+Test for the low-level RTT driver.

tests/periph_rtt/main.c

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief       Test for low-level Real Time Timer drivers
+ *
+ * This test will initialize the real-time timer and trigger an alarm printing
+ * 'Hello' every 10 seconds
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "cpu.h"
+#include "periph_conf.h"
+#include "periph/rtt.h"
+
+/* only compile this test if a RTT device is defined */
+#if RTT_NUMOF
+
+#define TICKS_TO_WAIT       (10 * RTT_FREQUENCY)
+
+void cb(void *arg)
+{
+    (void)arg;
+    uint32_t now;
+
+    now = rtt_get_counter() + TICKS_TO_WAIT;
+    now = (now > RTT_MAX_VALUE) ? now - RTT_MAX_VALUE : now;
+    rtt_set_alarm(now, cb, 0);
+    puts("Hello");
+}
+
+
+int main(void)
+{
+    puts("\nRIOT RTT low-level driver test");
+    puts("This test will display 'Hello' every 10 seconds\n");
+
+    puts("Initializing the RTT driver");
+    rtt_init();
+
+    puts("Setting initial alarm");
+    rtt_set_alarm(TICKS_TO_WAIT, cb, 0);
+
+    puts("Done setting up the RTT, wait for many Hellos");
+    return 0;
+}
+
+#else
+
+int main(void)
+{
+    puts("\nRIOT RTT low-level driver test");
+    puts("There are no RTT devices defined for this board!");
+
+    return 0;
+}
+
+#endif /* RTT_NUMOF */