Martin Johnson / STM32F3-Discovery

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Dependents:   Space_Invaders_Demo neopixels gpio_test_stm32f3_discovery gpio_test_systimer ... more

Files at this revision

API Documentation at this revision

Revision 1:f8e3e71af478, committed 2018-04-26

Comitter:
MartinJohnson
Date:
Thu Apr 26 03:11:18 2018 +0000
Parent:
0:404f5a4f1385
Commit message:
Add stdio.h serial I/O support for the version D discovery board.

Changed in this revision

src/startup_stm32f303xc.s Show annotated file Show diff for this revision Revisions of this file
src/system_stm32f30x.c Show annotated file Show diff for this revision Revisions of this file 
--- a/src/startup_stm32f303xc.s	Mon May 09 04:00:25 2016 +0000
+++ b/src/startup_stm32f303xc.s	Thu Apr 26 03:11:18 2018 +0000
@@ -375,8 +375,8 @@
             ;     IF      :DEF:__MICROLIB
                 
                  EXPORT  __initial_sp
-     ;            EXPORT  __heap_base
-     ;            EXPORT  __heap_limit
+;                 EXPORT  __heap_base
+;                 EXPORT  __heap_limit
                 
             ;     ELSE
                 
@@ -386,10 +386,10 @@
 ;__user_initial_stackheap
 
 ;                 LDR     R0, =  Heap_Mem
- ;                LDR     R1, =(Stack_Mem + Stack_Size)
- ;                LDR     R2, = (Heap_Mem +  Heap_Size)
- ;                LDR     R3, = Stack_Mem
- ;                BX      LR
+;                 LDR     R1, =(Stack_Mem + Stack_Size)
+;                 LDR     R2, = (Heap_Mem +  Heap_Size)
+;                 LDR     R3, = Stack_Mem
+;                 BX      LR
 ;
 ;                 ALIGN
 

--- a/src/system_stm32f30x.c	Mon May 09 04:00:25 2016 +0000
+++ b/src/system_stm32f30x.c	Thu Apr 26 03:11:18 2018 +0000
@@ -197,6 +197,49 @@
 #endif  
 }
 
+struct __FILE { int handle; };
+
+typedef struct __FILE FILE;
+
+FILE __stdout;
+FILE __stdin;
+
+static int serial_init_done=0;
+
+static void serial_init() {
+    if(!serial_init_done) {
+        serial_init_done=1;
+        RCC->AHBENR |= RCC_AHBPeriph_GPIOC;
+        RCC->APB2ENR |= RCC_APB2Periph_USART1;
+        GPIOC->AFR[0] = (GPIOC->AFR[0] & 0xff00ffff) | 0x770000; // alt funcs for GPIOC4 and 5 are 7
+        GPIOC->OSPEEDR |= 0xf00; // speed high
+        GPIOC->OTYPER &= ~0x30; // output type pp
+        GPIOC->MODER = (GPIOC->MODER & ~0xf00) | 0xa00; // mode af
+        GPIOC->PUPDR = (GPIOC->PUPDR & ~0xf00) | 0x500; // pull up
+        USART1->CR1 &= ~USART_CR1_UE; // disable so we can change settings
+        USART1->CR2 = (USART1->CR2 & ~USART_CR2_STOP) | USART_StopBits_1;
+        USART1->CR1 = (USART1->CR1 & 0xFFFFE6F3) | USART_WordLength_8b | USART_Parity_No | USART_Mode_Rx | USART_Mode_Tx;
+        USART1->CR3 = (USART1->CR3 & 0xFFFFFCFF) | USART_HardwareFlowControl_None;
+        USART1->BRR = SystemCoreClock/115200; // set baud rate
+        USART1->CR1 |= USART_CR1_UE; // enable serial port
+    }
+}
+
+int fputc(int ch, FILE *f) {
+    serial_init();
+    USART1->TDR = ch & 0x1ff;
+    while (!(USART1->ISR & USART_FLAG_TXE));
+    return ch;
+}
+
+int fgetc(FILE *f) {
+    serial_init();
+    if(USART1->ISR & USART_FLAG_ORE)
+        USART1->ISR &= ~USART_FLAG_ORE;
+    while(!(USART1->ISR & USART_FLAG_RXNE));
+    return USART1->RDR & 0xff;
+}
+
 /**
    * @brief  Update SystemCoreClock variable according to Clock Register Values.
   *         The SystemCoreClock variable contains the core clock (HCLK), it can