8 #define RXNE ((*USART1_SR >> 5) & 0x1)
13 uint8_t buf[UARTBUF] ;
19 void * uart_handler() {
21 //uart_puts("echo: ");
23 char echochar = *USART1_DR;
24 //uart_putc(echochar);
25 linefeed.buf[linefeed.wpos++] = echochar;
26 if (linefeed.wpos == UARTBUF)
28 //regw_u32(USART1_DR, echochar, 0, O_WRITE);
36 regw_u32(RCC_APB2ENR, 0x4005, 0, SETBIT);// enable clock to UART1, AFIO and GPIOA
38 /* (after enable GPIOA), on PA9&PA10 and set mode
39 * to alternative output */
40 regw_u32(GPIOA_CRH, 0x444444D4, 0, OWRITE);
41 regw_u8(AFIO_EVCR, 0x89, 0, OWRITE);// set event control register, output on PA, Pin 9
43 //disable temporarily to set values
44 regw_u8(USART1_CR1, 0x0, 13, SETBIT);
46 /* baud rate 115200, 8MHz / (16 * USARTDIV)
48 * FRACTION: 16 x 0.34 = 0d5.44 0d5 -> 0x5
49 * MANTISSA: 0d4.34 0d4 -> 0x4
52 regw_u32(USART1_BRR, 0x00000045, 0, OWRITE);
53 regw_u32(USART1_CR2, 0x0000, 0, OWRITE); //set stop bit, default is 1 stop bit 0x00
55 /* parity = 8 bit, UART1 enabled,
56 * TX and RX enabled, interrupts enabled */
57 //regw_u32(USART1_CR1, 0x000030AC, 0, O_WRITE);
58 regw_u32(USART1_CR1, 0x0000302C, 0, OWRITE);
60 ivt_set_gate(53, uart_handler, 0);
62 *NVIC_ISER1 = (1 << 5); // Enable UART interrupt at NVIC
66 for (int i = 0; i < 100; i++);
69 extern void uart_putc(unsigned char ch) {
72 while (*USART1_SR & 0x0C) { } // transmit data register empty and complete
73 regw_u8(USART1_DR, 0x0D, 0, OWRITE); // return line
76 while (*USART1_SR & 0x0C) {}
77 regw_u8(USART1_DR, ch, 0, OWRITE);
82 char uart_getc(void) {
85 if (linefeed.rpos != linefeed.wpos) {
86 c = linefeed.buf[linefeed.rpos++];
87 if (linefeed.rpos == UARTBUF)
96 extern void uart_puts(unsigned char *str) {
98 for (i = 0; i < strlen(str); i++) {