Revision 0:fc439458a359, committed 2013-11-23

Comitter:

Sissors

Date:

Sat Nov 23 11:35:14 2013 +0000

Child:

1:92f4c2b52771

Commit message:

v1.0
;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WakeUp.cpp	Sat Nov 23 11:35:14 2013 +0000
@@ -0,0 +1,72 @@
+#include "WakeUp.h"
+
+FunctionPointer WakeUp::callback;
+float WakeUp::cycles_per_ms = 10.0;
+
+void WakeUp::set_ms(uint32_t ms)
+{
+    //Enable clock to register interface:
+    LPC_SYSCON->SYSAHBCLKCTRL |= 1<<9;
+
+    //Clear the counter:
+    LPC_WKT->CTRL |= 1<<2;
+    if (ms != 0) {
+        //Enable clock to register interface:
+        LPC_SYSCON->SYSAHBCLKCTRL |= 1<<9;
+
+        //Set 10kHz timer as source, and just to be sure clear status bit
+        LPC_WKT->CTRL = 3;
+
+        //Enable the 10kHz timer
+        LPC_PMU->DPDCTRL |= (1<<2) | (1<<3);
+
+        //Set interrupts
+        NVIC_SetVector(WKT_IRQn, (uint32_t)WakeUp::irq_handler);
+        NVIC_EnableIRQ(WKT_IRQn);
+
+        //Load the timer
+        LPC_WKT->COUNT = (uint32_t)((float)ms * cycles_per_ms);
+
+    } else {
+        //Disable clock to register interface:
+        LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<9);
+
+        //Disable the 10kHz timer
+        LPC_PMU->DPDCTRL &= ~((1<<2) | (1<<3));
+    }
+}
+
+void WakeUp::irq_handler(void)
+{
+    //Clear status
+    LPC_WKT->CTRL |= 2;
+
+    //Disable clock to register interface:
+    LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<9);
+
+    //Disable the 10kHz timer
+    LPC_PMU->DPDCTRL &= ~((1<<2) | (1<<3));
+
+    callback.call();
+}
+
+void WakeUp::calibrate(void)
+{
+    cycles_per_ms = 10.0;
+    set_ms(1100);
+    wait_ms(100);
+
+    uint32_t prevread = LPC_WKT->COUNT;
+    uint32_t read = LPC_WKT->COUNT;
+    while( read != prevread) {
+        prevread = read;
+        read = LPC_WKT->COUNT;
+    }
+
+    uint32_t ticks = 11000 - read;
+
+    cycles_per_ms = ticks / 100.0;
+    set_ms(0);
+}
+
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WakeUp.h	Sat Nov 23 11:35:14 2013 +0000
@@ -0,0 +1,71 @@
+#include "mbed.h"
+
+/**
+* Class to make use of the LPC81x's low power wake-up timer.
+*
+* One of the methods of waking up from deepsleep/powerdown is using the wake-up timer.
+* This is an ultra low-power timer that can run from an always-on 10kHz clock source.
+* So while normal timers are shut-down, this one still runs, consuming only roughly 1uA.
+* If the timer does not need to run everything is shut down again by the library.
+*
+* This class can also be used as general purpose interrupt timer, although just using 
+* the default Timer library is probably a better idea for that.
+*
+* Example program: http://mbed.org/users/Sissors/code/LPC812_Sleep_HelloWorld/
+*/
+class WakeUp
+{
+public:
+    /**
+    * Set the timeout
+    *
+    * @param s - required time in seconds
+    */
+    static void set(uint32_t s) {
+        set_ms(1000 * s);
+    }
+    
+    /**
+    * Set the timeout
+    *
+    * @param ms - required time in milliseconds
+    */
+    static void set_ms(uint32_t ms);
+    
+    /**
+    * Attach a function to be called after timeout
+    *
+    * This is optional, if you just want to wake up you 
+    * do not need to attach a function.
+    *
+    * Also supports normal way to attach member functions
+    * (not documented for simplicity)
+    *
+    * @param *function - function to call
+    */
+    static void attach(void (*function)(void)) {
+        callback.attach(function);
+    }
+
+    template<typename T>
+    static void attach(T *object, void (T::*member)(void)) {
+        callback.attach(object, member);
+    }
+    
+    /**
+    * Calibrate the timer
+    *
+    * The 10kHz timer has a very bad accuracy: +/- 45%.
+    * This function calibrates it for 100ms against the main clock.
+    * So you get almost that accuracy by calling this function. 
+    *
+    * Warning: Blocks for 100ms!
+    */
+    static void calibrate(void);
+
+
+private:
+    static FunctionPointer callback;
+    static void irq_handler(void);
+    static float cycles_per_ms;
+};
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