Add main file stub and display demo

Initial MVP of a main file that prints a text on the radio display.
The code is already platform independent, to be ported effortlessly
to any of the supported platforms.

meson.build

@@ -78,7 +78,7 @@ endif
 
 
 ## TYT MD380
-md380_src = src + ['tests/platform/MD380_display.c',
+md380_src = src + ['openrtx/src/main.c',
                    'platform/mcu/STM32F4xx/boot/startup.c',
                    'platform/mcu/STM32F4xx/boot/libc_integration.c',
                    'platform/mcu/STM32F4xx/drivers/usb/usb_bsp.c',

openrtx/src/main.c

@@ -0,0 +1,117 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Izzo IU2NUO, Niccolò Izzo IU2KIN and   *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <app_cfg.h>
+#include <os.h>
+#include <lib_mem.h>
+#include <stdio.h>
+#include "stm32f4xx.h"
+#include "gpio.h"
+#include "delays.h"
+#include "display.h"
+#include "graphics.h"
+
+static OS_TCB        startTCB;
+static CPU_STK_SIZE  startStk[APP_CFG_TASK_START_STK_SIZE];
+static void startTask(void *arg);
+
+static OS_TCB        uiTaskTCB;
+static CPU_STK_SIZE  uiTaskStk[128];
+static void uiTask(void *arg);
+
+int main(void)
+{
+    OS_ERR err;
+
+    OSInit(&err);
+
+    OSTaskCreate((OS_TCB     *)&startTCB,
+                 (CPU_CHAR   *)" ",
+                 (OS_TASK_PTR ) startTask,
+                 (void       *) 0,
+                 (OS_PRIO     ) APP_CFG_TASK_START_PRIO,
+                 (CPU_STK    *)&startStk[0],
+                 (CPU_STK     )startStk[APP_CFG_TASK_START_STK_SIZE / 10u],
+                 (CPU_STK_SIZE) APP_CFG_TASK_START_STK_SIZE,
+                 (OS_MSG_QTY  ) 0,
+                 (OS_TICK     ) 0,
+                 (void       *) 0,
+                 (OS_OPT      )(OS_OPT_TASK_STK_CHK | OS_OPT_TASK_STK_CLR),
+                 (OS_ERR     *)&err);
+
+    OSStart(&err);
+
+    for(;;) ;
+    return 0;
+}
+
+static void startTask(void* arg)
+{
+
+    (void) arg;
+    OS_ERR err;
+
+    gpio_setMode(GPIOE, 0, OUTPUT);
+    gpio_setMode(GPIOE, 1, OUTPUT);
+
+    CPU_Init();
+    OS_CPU_SysTickInitFreq(SystemCoreClock);
+
+    OSTaskCreate((OS_TCB     *)&uiTaskTCB,
+                (CPU_CHAR   *)" ",
+                (OS_TASK_PTR ) uiTask,
+                (void       *) 0,
+                (OS_PRIO     ) 5,
+                (CPU_STK    *)&uiTaskStk[0],
+                (CPU_STK     ) 0,
+                (CPU_STK_SIZE) 128,
+                (OS_MSG_QTY  ) 0,
+                (OS_TICK     ) 0,
+                (void       *) 0,
+                (OS_OPT      )(OS_OPT_TASK_STK_CHK | OS_OPT_TASK_STK_CLR),
+                (OS_ERR     *)&err);
+
+    while(1) ;
+}
+
+static void uiTask(void *arg)
+{
+    (void) arg;
+    OS_ERR os_err;
+
+    // Init the graphic stack
+    gfx_init();
+    gfx_setBacklightLevel(255);
+
+    point_t origin = {0, SCREEN_HEIGHT / 2};
+    color_t color_yellow = {250, 180, 19};
+    char *buffer = "OpenRTX";
+
+    // Task infinite loop
+    while(DEF_ON)
+    {
+        gfx_clearScreen();
+        gfx_print(origin, buffer, FONT_SIZE_4, TEXT_ALIGN_CENTER, color_yellow);
+        gfx_render();
+        while(gfx_renderingInProgress());
+        OSTimeDlyHMSM(0u, 0u, 0u, 100u, OS_OPT_TIME_HMSM_STRICT, &os_err);
+    }
+}