main.cpp

00001 #include "mbed.h"
00002 
00003 //WATHDOG ENABLED IN OUR KL25Z_SystemInit.c (overloading library function SystemInit.c)
00004 // It happens in this uC after reset watchdog is enabled with timeout=1024ms (2^10*LPO=1KHz)
00005 //  so mbed developers to allow a learning use of this board disable it on SystemInit.c
00006 // **BUT** SIM_COPC register can only be written once after reset and so it can not be enabled later
00007 //  I think best solution is to overload SystemInit() using:   void $Sub$$SystemInit (void) {
00008 //  original SystemInit() does not appear in export, it must be dowloaded from:
00009 // https://developer.mbed.org/users/mbed_official/code/mbed-src/file/a11c0372f0ba/targets/cmsis/TARGET_Freescale/TARGET_KLXX/TARGET_KL25Z/system_MKL25Z4.c
00010 //  you can arrive there from:
00011 // https://developer.mbed.org/handbook/mbed-SDK and https://developer.mbed.org/users/mbed_official/code/mbed-src/
00012 //
00013 // MORE on this on: https://developer.mbed.org/users/chris/notebook/Patching-functions-and-libraries/
00014 // and searching "ARM Compiler toolchain Using the Linker" "Using $Super$$ and $Sub$$ to patch symbol definitions"
00015 
00016 // Kick (feed, reload) our watchdog timer
00017 void wdt_kick(){
00018     SIM->SRVCOP = (uint32_t)0x55u;
00019     SIM->SRVCOP = (uint32_t)0xAAu;
00020 }
00021 
00022 // That set RED LED ON, do that first to evaluate boot time of peripherals
00023 #define LIGHT 0
00024 #define DARK 1
00025 DigitalOut led_red(LED_RED, LIGHT);
00026 DigitalOut led_green(LED_GREEN, DARK);
00027 DigitalOut led_blue(LED_BLUE, DARK);
00028 
00029 //Virtual serial port over USB using inboard second USB connector (USBKL25Z port)
00030 #include "USBSerial.h"
00031 //USBSerial pc;
00032 //...( vendor_id, product_id, product_release, connect_blocking )
00033 USBSerial pc( 0x1f00, 0x2012, 0x0001, false );
00034 //REMEMBER TO USE: class USBSerial -> connect_blocking = false (default is true)
00035 //  to avoid block of program when no USB cable connected in USBKL25Z port
00036 //NOTE: USBSerial still blocks program when closing serial terminal, that is fixed by our watchdog
00037 
00038 
00039 int main(void) {
00040     //to evaluate boot time I set led RED ON at the beginning of our main.cpp. TODO?: do it in SystemInit?
00041     led_blue = DARK;
00042     led_green = DARK;
00043     led_red = DARK;
00044     while(1)
00045     {
00046         led_blue = LIGHT;
00047         pc.printf("I am a virtual serial port\r\n");    // THAT COULD BLOCK
00048         wdt_kick();
00049         led_blue = DARK;
00050         wait(0.5);
00051     }
00052 }