Quadrotor from scratch
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79 lines
1.2 KiB

#include "uart.h"
#define UARTBASE 0xE000C000
#define RBR 0x00
#define THR 0x00
#define DLL 0x00
#define DLM 0x04
#define IER 0x04
#define IIR 0x08
#define FCR 0x08
#define LCR 0x0c
#define LSR 0x14
#define SCR 0x1c
#define ACR 0x20
#define FDR 0x28
#define TER 0x30
#define UREG(x) (((volatile unsigned char *)UARTBASE)[x])
#define U0THRE ((UREG(LSR) & (1<<5))) /* UART0 transmitter holding register is empty */
#define U0DR ((UREG(LSR) & (1<<0))) /* UART0 data ready */
void init_uart(void)
{
UREG(FDR) = 0x10; /* DivAddVal = 0, MulVal = 1 */
UREG(LCR) = 0x80;
UREG(DLM) = 0x00;
UREG(DLL) = 0x08; /* 14745600 / (16*115200) */
UREG(LCR) = 0x13;
UREG(FCR) = 0x07;
}
void putch(char c) {
while (!U0THRE);
UREG(THR) = c;
}
void putstr(char *s) {
while (*s) putch(*s++);
}
void putint(unsigned int n) {
char s[11];
int i;
i = 10;
s[i] = '\0';
do {
s[--i] = n % 10 + '0';
} while ((n /= 10) > 0);
putstr(s+i);
}
void puthex(unsigned int n) {
char s[9];
int i;
i = 8;
s[i] = '\0';
do {
int x = n % 16;
if (x > 9)
x += 'A' - '0' - 10;
s[--i] = x + '0';
} while ((n /= 16) > 0);
putstr(s+i);
}
char getch(void) {
while (!U0DR);
return UREG(RBR);
}