systick testing and simplification

ripped out marti's SystemTick for the sake of simplicity and added a
systick_resume function to libmaple. new example program demonstrates
the functionality, also demonstrates micros()/USB bug

7 files changed, 68 insertions, 85 deletions

diff --git a/examples/test-systick.cpp b/examples/test-systick.cpp
new file mode 100644
index 0000000..247892d
--- /dev/null
+++ b/examples/test-systick.cpp
@@ -0,0 +1,60 @@
+// Tests the SysTick enable/disable functions
+//
+#include "wirish.h"
+#include "systick.h"
+
+#define LED_PIN 13
+#define PWM_PIN  2
+#define BUT     38
+
+void setup()
+{
+    /* Set up the LED to blink  */
+    pinMode(LED_PIN, OUTPUT);
+
+    /* Turn on PWM on pin PWM_PIN */
+    pinMode(PWM_PIN, PWM);
+    pwmWrite(PWM_PIN, 0x8000);
+
+    pinMode(BUT, INPUT_PULLDOWN);
+}
+
+int toggle = 0;
+long time = 0;
+
+void loop() {
+    toggle ^= 1;
+    digitalWrite(LED_PIN, toggle);
+
+    // An artificial delay
+    int16 i = 1;
+    float j = 1;
+    for(i=0; i<6553; i++) {
+        j = sqrt(j) + 1; 
+    }
+        
+    if(digitalRead(BUT)) {
+        systick_disable();
+    } else {
+        systick_resume();
+    }
+
+    //SerialUSB.println(micros());      // there is a bug with this
+    SerialUSB.println(millis());
+}
+
+// Force init to be called *first*, i.e. before static object allocation.
+// Otherwise, statically allocated object that need libmaple may fail.
+ __attribute__(( constructor )) void premain() {
+    init();
+}
+
+int main(void)
+{
+    setup();
+
+    while (1) {
+        loop();
+    }
+    return 0;
+}
diff --git a/libmaple/systick.c b/libmaple/systick.c
index 456ac2f..9fbb152 100644
--- a/libmaple/systick.c
+++ b/libmaple/systick.c
@@ -58,6 +58,13 @@ void systick_disable() {
   __write(SYSTICK_CSR, SYSTICK_SRC_HCLK);
 }
 
+void systick_resume() {
+  /* re-enable init registers without changing relead_val */
+  __write(SYSTICK_CSR, SYSTICK_SRC_HCLK |
+                       SYSTICK_ENABLE   |
+                       SYSTICK_TICKINT);
+}
+
 void SysTickHandler(void) {
     systick_timer_millis++;
 }
diff --git a/libmaple/systick.h b/libmaple/systick.h
index 86284f8..80e2fde 100644
--- a/libmaple/systick.h
+++ b/libmaple/systick.h
@@ -44,6 +44,7 @@ extern "C"{
 
 void systick_init(uint32 reload_val);
 void systick_disable();
+void systick_resume();
 
 static inline uint32 systick_get_count(void) {
     return __read(SYSTICK_CNT);
diff --git a/wirish/SystemTick.cpp b/wirish/SystemTick.cpp
deleted file mode 100644
index 8631a70..0000000
--- a/wirish/SystemTick.cpp
+++ /dev/null
@@ -1,40 +0,0 @@
-/* *****************************************************************************
- * The MIT License
- *
- * Copyright (c) 2010 Marti F. Bolivar.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- * ****************************************************************************/
-
-#include "SystemTick.h"
-#include "systick.h"
-#include "time.h"
-
-SysTick::SysTick(void) {
-}
-
-void SysTick::begin(void) {
-  systick_init(MAPLE_RELOAD_VAL);
-}
-
-void SysTick::end(void) {
-  systick_disable();
-}
-
-SysTick SystemTick;
diff --git a/wirish/SystemTick.h b/wirish/SystemTick.h
deleted file mode 100644
index f0dd876..0000000
--- a/wirish/SystemTick.h
+++ /dev/null
@@ -1,43 +0,0 @@
-/* *****************************************************************************
- * The MIT License
- *
- * Copyright (c) 2010 Marti F. Bolivar.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- * ****************************************************************************/
-
-/**
- * @brief wrapper class for starting and stopping SysTick interrupts.
- */
-
-#ifndef _SYSTEMTICK_H_
-#define _SYSTEMTICK_H_
-
-#include "systick.h"
-
-class SysTick {
- public:
-  SysTick(void);
-  void begin(void);
-  void end(void);
-};
-
-extern SysTick SystemTick;
-
-#endif
diff --git a/wirish/rules.mk b/wirish/rules.mk
index 18d93b2..cb5a69f 100644
--- a/wirish/rules.mk
+++ b/wirish/rules.mk
@@ -26,7 +26,6 @@ cppSRCS_$(d) := wirish_math.cpp          \
                 usb_serial.cpp 	         \
 		HardwareTimer.cpp        \
                 cxxabi-compat.cpp        \
-		SystemTick.cpp
 
 cFILES_$(d) := $(cSRCS_$(d):%=$(d)/%)
 cppFILES_$(d) := $(cppSRCS_$(d):%=$(d)/%)
diff --git a/wirish/wirish.h b/wirish/wirish.h
index d293901..7ede77c 100644
--- a/wirish/wirish.h
+++ b/wirish/wirish.h
@@ -45,7 +45,6 @@
 #include "HardwareSPI.h"
 #include "HardwareSerial.h"
 #include "usb_serial.h"
-#include "SystemTick.h"
 #include "HardwareTimer.h"
 #endif