Delays driver for AT32F421 MCU

meson.build

@@ -260,6 +260,7 @@ at32f421_src = ['platform/mcu/AT32F421/boot/startup.cpp',
                 'platform/mcu/AT32F421/boot/bsp.cpp',
                 'platform/mcu/AT32F421/boot/libc_integration.cpp',
                 'platform/mcu/AT32F421/drivers/gpio.c',
+                'platform/mcu/AT32F421/drivers/delays.cpp',
                 'platform/mcu/CMSIS/Device/Artery/AT32F421/Source/system_at32f421.c']
 
 at32f421_inc = ['platform/mcu/AT32F421',

platform/mcu/AT32F421/drivers/delays.cpp

@@ -0,0 +1,70 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Silvano Seva IU2KWO                             *
+ *                     and Niccolò Izzo IU2KIN                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <interfaces/delays.h>
+#include <miosix.h>
+
+/**
+ * Implementation of the delay functions for AT32F421 MCU.
+ * Delays have been calibrated for a clock frequency of 120MHz.
+ */
+
+void delayUs(unsigned int useconds)
+{
+    // This delay has been calibrated to take x microseconds
+    // It is written in assembler to be independent on compiler optimization
+    asm volatile("           mov   r1, #29    \n"
+                 "           mul   r2, %0, r1 \n"
+                 "           mov   r1, #0     \n"
+                 "___loop_u: cmp   r1, r2     \n"
+                 "           itt   lo         \n"
+                 "           addlo r1, r1, #1 \n"
+                 "           blo   ___loop_u  \n"::"r"(useconds):"r1","r2");
+}
+
+void delayMs(unsigned int mseconds)
+{
+    register const unsigned int count=23175;
+
+    for(unsigned int i=0;i<mseconds;i++)
+    {
+        // This delay has been calibrated to take 1 millisecond
+        // It is written in assembler to be independent on compiler optimization
+        asm volatile("           mov   r1, #0     \n"
+                     "___loop_m: cmp   r1, %0     \n"
+                     "           itt   lo         \n"
+                     "           addlo r1, r1, #1 \n"
+                     "           blo   ___loop_m  \n"::"r"(count):"r1");
+    }
+}
+
+void sleepFor(unsigned int seconds, unsigned int mseconds)
+{
+    unsigned int time = (seconds * 1000) + mseconds;
+    miosix::Thread::sleep(time);
+}
+
+void sleepUntil(long long timestamp)
+{
+    miosix::Thread::sleepUntil(timestamp);
+}
+
+long long getTick()
+{
+    return miosix::getTick();
+}