uart small ping pong receive, update of register functions

[cortex-from-scratch] / uart.c

diff --git a/uart.c b/uart.c
index a3905c4..4751645 100644 (file)
--- a/uart.c
+++ b/uart.c
@@ -4,14 +4,39 @@
 #include <stm32.h>
 #include <mmap.h>
 
+#define RXNE ((*USART1_SR >> 5) & 0x1)
+
+#define O_WRITE 0x01
+#define SET 0x02
+#define CLEAR 0x03
+
+void * uart_handler() {
+
+       uart_puts("\n echo: ");
+       while (RXNE) {
+               char echochar = *USART1_DR;
+       //      regw_u8(USART1_DR, echochar, 0, O_WRITE);
+       uart_putc(echochar);
+       }  
+//for(;;);
+
+}
 void uart_init() {
 
+       // global interrupt setup
+//     regw_u32(EXTI_IMR, 0x000FFFFF, 0, O_WRITE);
+//     regw_u32(EXTI_RTSR, 0x000FFFFF, 0, O_WRITE);
+
+               
+       regw_u32(RCC_APB2ENR, 0x4005, 0, SET);// enable clock to UART1, AFIO and GPIOA
        
-       *RCC_APB2ENR = 0x4005; // enable clock to UART1, AFIO and GPIOA
-       *GPIOA_CRH = 0x444444D4; // (after enable GPIOA), on PA9&PA10 and set mode to alternative output
-       *AFIO_EVCR = 0x89; // (after enable) set event control register, output on PA, Pin 9
+       /* (after enable GPIOA), on PA9&PA10 and set mode
+        *  to alternative output */
+       regw_u32(GPIOA_CRH, 0x444444D4, 0, O_WRITE);
+       regw_u8(AFIO_EVCR, 0x89, 0, O_WRITE);// set event control register, output on PA, Pin 9
 
-       *USART1_CR1 = (0 << 13); // disable temporarily to set values
+       //disable temporarily to set values
+       regw_u8(USART1_CR1, 0x0, 13, SET);
 
        /* baud rate 115200,  8MHz / (16 * USARTDIV)
         * USARTDIV = 4.34
@@ -19,28 +44,17 @@ void uart_init() {
         * MANTISSA: 0d4.34 0d4 -> 0x4 
         * USART_BRR = 0x45*/
 
-       /* baud rate 2400 
-        * 
-        * 16 * 0.33 -> 0x5
-        * 208 -> 0x34 */
-
-       *USART1_BRR = (volatile uint32_t) 0x00000045;
+       regw_u32(USART1_BRR, 0x00000045, 0, O_WRITE);
+       regw_u32(USART1_CR2, 0x0000, 0, O_WRITE); //set stop bit, default is 1 stop bit 0x00
        
-       *USART1_CR2 = (volatile uint32_t) 0x0000; // set stop bit, default is 1 stop bit 0x00
-       // enable DMA 
-       // *USART1_CR3 = 0x0C0; 
        /* parity = 8 bit, UART1 enabled,
         * TX and RX enabled, interrupts enabled */
-       *USART1_CR1 = (volatile uint32_t) 0x000030AC; 
-
-/* 
- * Configure UART0:
-       1. Disable the UART by clearing the UARTEN bit in the UARTCTL register.
-       2. Write the integer portion of the BRD to the UARTIBRD register.
-       3. Write the fractional portion of the BRD to the UARTFBRD register.
-       4. Write the desired serial parameters to the UARTLCRH register
-       5. Enable the UART by setting the UARTEN bit in the UARTCTL register.
-*/
+       //regw_u32(USART1_CR1, 0x000030AC, 0, O_WRITE);
+       regw_u32(USART1_CR1, 0x0000302C, 0, O_WRITE);
+
+       ivt_set_gate(53, uart_handler, 0);
+       
+       *NVIC_ISER1 = (1 << 5); // Enable UART interrupt at NVIC
 }
 
 void wait() {
@@ -51,34 +65,33 @@ extern void uart_putc(unsigned char ch) {
        
        if (ch == '\n') {
                while (*USART1_SR & 0x0C) { } // transmit data register empty and complete
-               *USART1_DR = 0x0D; // return line
+               regw_u8(USART1_DR, 0x0D, 0, O_WRITE); // return line
        }
 
-
        while (*USART1_SR & 0x0C) {} 
-               *USART1_DR = ch;
+               regw_u8(USART1_DR, ch, 0, O_WRITE);
 
-
-       
        wait();
 }
 
-extern void uart_puts(unsigned char *str)
-{
-
+extern void uart_puts(unsigned char *str) {
     int i;
-
-    for (i = 0; i < strlen(str); i++)
-    {
+    for (i = 0; i < strlen(str); i++)     {
         uart_putc(str[i]);
     }
 }
 
 
 
-char * uart_read() {
+char uart_read() { 
 
-       return NULL;
+       /* while (buffer not empty)
+        *      read()
+        *      uart_putc(ch) // echo
+        *              if ch = enter
+        *              process inquiry.
+        */
+       
 }