baud zero divide

V203/usb/ch32v203/startup.cpp

@@ -1,9 +1,9 @@
 #include "system.h"
 typedef __SIZE_TYPE__ size_t;
 extern "C" {
-  extern void handle_reset () __attribute__((naked,nothrow,used));
-  extern void user_init ()    __attribute__((used));
-  extern int  main      ()    __attribute__((used));
+  [[using gnu: naked,nothrow,used]] extern void handle_reset ();
+  [[gnu::used]] extern void user_init ();
+  [[gnu::used]] extern int  main      ();
   // This is required to allow pure virtual functions to be defined.
   extern void __cxa_pure_virtual() { while (1); }
 
@@ -14,41 +14,17 @@ extern "C" {
   extern uint32_t _data_vma;
   extern uint32_t _edata;
 
-  extern void (*__preinit_array_start[]) (void) __attribute__((weak));
-  extern void (*__preinit_array_end[]) (void) __attribute__((weak));
-  extern void (*__init_array_start[]) (void) __attribute__((weak));
-  extern void (*__init_array_end[]) (void) __attribute__((weak));
+  [[gnu::weak]] extern void (*__preinit_array_start[]) (void);
+  [[gnu::weak]] extern void (*__preinit_array_end[]) (void);
+  [[gnu::weak]] extern void (*__init_array_start[]) (void);
+  [[gnu::weak]] extern void (*__init_array_end[]) (void);
 
-  static void __init_array () {
-      uint32_t * dst, * end;
-
-      /* Zero fill the bss section */
-      dst = &_sbss;
-      end = &_ebss;
-      while (dst < end) * dst++ = 0U;
-      /* Copy data section from flash to RAM */
-      uint32_t * src;
-      src = &_data_lma;
-      dst = &_data_vma;
-      end = &_edata;
-      if (src != dst) {
-        while (dst < end) * dst++ = * src++;
-      }
-      
-      size_t count;
-      /* Pro Cortex-Mx bylo toto zbytečné, lze předpokládat, že je to tak i zde.
-      count = __preinit_array_end - __preinit_array_start;
-      for (unsigned i = 0; i < count; i++)  __preinit_array_start[i]();
-      */
-      count = __init_array_end - __init_array_start;
-      for (unsigned i = 0; i < count; i++)  __init_array_start[i]();
-  }
   // If you don't override a specific handler, it will just spin forever.
-  void DefaultIRQHandler( void ) {
+  [[gnu::interrupt]] void DefaultIRQHandler( void ) {
       // Infinite Loop
       for (;;);
   }
-  void NMI_RCC_CSS_IRQHandler( void ) {
+  [[gnu::interrupt]] void NMI_RCC_CSS_IRQHandler( void ) {
       RCC.INTR.B.CSSC = RESET;	// clear the clock security int flag
   }
   #define ALIAS(f) __attribute__((nothrow,weak,alias(#f),used))
@@ -255,10 +231,35 @@ R"---(
 : : [main]"r"(user_init)/*, [InterruptVector]"r"(InterruptVector)*/
 : "t0", "memory" );
 }
+static void init_variables () {
+    uint32_t * dst, * end;
+
+    /* Zero fill the bss section */
+    dst = &_sbss;
+    end = &_ebss;
+    while (dst < end) * dst++ = 0U;
+    /* Copy data section from flash to RAM */
+    uint32_t * src;
+    src = &_data_lma;
+    dst = &_data_vma;
+    end = &_edata;
+    if (src != dst) {
+      while (dst < end) * dst++ = * src++;
+    }
+}    
+static void init_constructors () {
+    /* Pro Cortex-Mx bylo toto zbytečné, lze předpokládat, že je to tak i zde.
+    count = __preinit_array_end - __preinit_array_start;
+    for (unsigned i = 0; i < count; i++)  __preinit_array_start[i]();
+    */
+    const size_t count = __init_array_end - __init_array_start;
+    for (unsigned i = 0; i < count; i++)  __init_array_start[i]();
+}
 void user_init () {
+  init_variables();
   SystemInit();
   SystemCoreClockUpdate();
-  __init_array();
+  init_constructors();      // Konstruktory zavolat až po inicializaci hodin
   main ();
   for (;;);
 }

V203/usb/ch32v203/system.cpp

@@ -10,14 +10,13 @@ enum CLKSRC : uint32_t {
 static constexpr unsigned HSI_VALUE             = 8000000u;       /* Value of the Internal oscillator in Hz */
 static constexpr unsigned HSE_VALUE             = 8000000u;       /* Value of the External oscillator in Hz */
 /* In the following line adjust the External High Speed oscillator (HSE) Startup Timeout value */
-static constexpr unsigned SYSCLK_FREQ_96MHz_HSE = SYSTEM_CORE_CLOCK;
 static constexpr unsigned HSE_STARTUP_TIMEOUT   = 0x1000u;        /* Time out for HSE start up */
 // HSE i HSI mají frekvenci 8 MHz
 static constexpr uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 
-uint32_t SystemCoreClock = SYSCLK_FREQ_96MHz_HSE;                 /* System Clock Frequency (Core Clock) */
+uint32_t SystemCoreClock = SYSTEM_CORE_CLOCK;                     /* System Clock Frequency (Core Clock) */
 
-static void SetSysClockTo96_HSE(void) {
+static void SetSysClock_HSE(void) {
   __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
 
   RCC.CTLR.B.HSEON = SET;
@@ -45,7 +44,7 @@ static void SetSysClockTo96_HSE(void) {
       */
       r.B.PLLSRC   = SET;
       r.B.PLLXTPRE = RESET;
-      r.B.PLLMUL   = 10u;
+      r.B.PLLMUL   = 15u;     // or 10u for 96 MHz
       return r.R;
     });
     /* Enable PLL */
@@ -71,7 +70,7 @@ void SystemInit(void) {
   RCC.CTLR.R  &= 0xFFFBFFFFu;
   RCC.CFGR0.R &= 0xFF00FFFFu;
   RCC.INTR.R   = 0x009F0000u;    
-  SetSysClockTo96_HSE();
+  SetSysClock_HSE();
 }
 /*********************************************************************
  * @fn      SystemCoreClockUpdate
@@ -81,7 +80,7 @@ void SystemInit(void) {
  * @return  none
  */
 void SystemCoreClockUpdate (void) {
-  uint32_t tmp = 0, pllmull = 0, pllsource = 0, Pll_6_5 = 0;
+  uint32_t tmp = 0, pllmull = 0, pllsource = 0;
 
   tmp = RCC.CFGR0.B.SWS;
 
@@ -112,9 +111,6 @@ void SystemCoreClockUpdate (void) {
           SystemCoreClock = HSE_VALUE * pllmull;
         }
       }
-
-      if(Pll_6_5 == 1) SystemCoreClock = (SystemCoreClock / 2);
-
       break;
     default:
       SystemCoreClock = HSI_VALUE;
@@ -128,6 +124,7 @@ void SystemCoreClockUpdate (void) {
 static uint32_t p_us = 0u;
 static bool     timeout;
 void delay_init () {
+    // default clock is HCLK / 8
     p_us = SystemCoreClock / 8000000;
 }
 void delay_us (const unsigned dly) {

V203/usb/ch32v203/system.h

@@ -79,7 +79,7 @@ struct SysTick_Type {
     }
 };
 static SysTick_Type & SysTick = * reinterpret_cast<SysTick_Type * const> (0xE000F000);
-static constexpr unsigned SYSTEM_CORE_CLOCK = 96'000'000u;
+static constexpr unsigned SYSTEM_CORE_CLOCK = 144'000'000u; // or 96'000'000u
 extern "C" {
   extern uint32_t SystemCoreClock;
   extern void SystemCoreClockUpdate (void);

V203/usb/ch32v203/usart.cpp

@@ -69,6 +69,7 @@ uint32_t Usart::Down(const char * data, const uint32_t len) {
   return n;
 }
 void Usart::SetBaud (const uint32_t _baud) const {
+  if (_baud == 0u) return;                // ! zero divide
   const ONE_BIT b = USART1.CTLR1.B.UE;
   if (b == SET) USART1.CTLR1.B.UE = RESET;
   const uint32_t HCLK = SystemCoreClock;  // hodiny pro USART zde nejsou děleny