132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
#include <uart.h>
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#include <gpio.h>
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#include <stddef.h>
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/* Auxilary mini UART registers */
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#define AUX_ENABLE ((volatile unsigned int*)(MMIO_BASE+0x00215004))
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#define AUX_MU_IO ((volatile unsigned int*)(MMIO_BASE+0x00215040))
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#define AUX_MU_IER ((volatile unsigned int*)(MMIO_BASE+0x00215044))
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#define AUX_MU_IIR ((volatile unsigned int*)(MMIO_BASE+0x00215048))
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#define AUX_MU_LCR ((volatile unsigned int*)(MMIO_BASE+0x0021504C))
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#define AUX_MU_MCR ((volatile unsigned int*)(MMIO_BASE+0x00215050))
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#define AUX_MU_LSR ((volatile unsigned int*)(MMIO_BASE+0x00215054))
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#define AUX_MU_MSR ((volatile unsigned int*)(MMIO_BASE+0x00215058))
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#define AUX_MU_SCRATCH ((volatile unsigned int*)(MMIO_BASE+0x0021505C))
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#define AUX_MU_CNTL ((volatile unsigned int*)(MMIO_BASE+0x00215060))
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#define AUX_MU_STAT ((volatile unsigned int*)(MMIO_BASE+0x00215064))
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#define AUX_MU_BAUD ((volatile unsigned int*)(MMIO_BASE+0x00215068))
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int is_uart_init = 0;
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/**
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* Set baud rate and characteristics (115200 8N1) and map to GPIO
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*/
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void uart_init()
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{
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register unsigned int r;
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/* initialize UART */
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*AUX_ENABLE |=1; // enable UART1, AUX mini uart
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*AUX_MU_IER = 0;
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*AUX_MU_CNTL = 0;
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*AUX_MU_LCR = 3; // 8 bits
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*AUX_MU_MCR = 0;
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*AUX_MU_IER = 0;
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*AUX_MU_IIR = 0xc6; // disable interrupts
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*AUX_MU_BAUD = 270; // 115200 baud
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/* map UART1 to GPIO pins */
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r=*GPFSEL1;
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r&=~((7<<12)|(7<<15)); // gpio14, gpio15
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r|=(2<<12)|(2<<15); // alt5
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*GPFSEL1 = r;
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*GPPUD = 0; // enable pins 14 and 15
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r=150; while(r--) { asm volatile("nop"); }
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*GPPUDCLK0 = (1<<14)|(1<<15);
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r=150; while(r--) { asm volatile("nop"); }
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*GPPUDCLK0 = 0; // flush GPIO setup
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*AUX_MU_CNTL = 3; // enable Tx, Rx
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is_uart_init = 1;
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}
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/**
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* Send a character
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*/
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void uart_send(unsigned int c) {
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/* wait until we can send */
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do{asm volatile("nop");}while(!(*AUX_MU_LSR&0x20));
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/* write the character to the buffer */
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*AUX_MU_IO=c;
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}
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uint8_t uart_getb()
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{
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uint8_t r;
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/* wait until something is in the buffer */
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do{asm volatile("nop");}while(!(*AUX_MU_LSR&0x01));
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/* read it and return */
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r=(uint8_t)(*AUX_MU_IO);
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return r;
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}
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/**
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* Receive a character
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*/
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char uart_getc() {
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char r = (char)uart_getb();
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/* convert carrige return to newline */
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return r=='\r'?'\n':r;
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}
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/**
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* Display a string
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*/
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void uart_puts(const char *s) {
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while(*s) {
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/* convert newline to carrige return + newline */
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if(*s=='\n')
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uart_send('\r');
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uart_send(*s++);
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}
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}
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/**
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* Display a binary value in hexadecimal
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*/
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void uart_hex(const unsigned int d) {
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unsigned int n;
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int c;
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for(c=28;c>=0;c-=4) {
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// get highest tetrad
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n=(d>>c)&0xF;
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// 0-9 => '0'-'9', 10-15 => 'A'-'F'
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n+=n>9?0x37:0x30;
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uart_send(n);
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}
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}
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void uart_int(int d)
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{
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unsigned int buf[11];
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int size = 0;
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if (d == 0) {
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uart_send((unsigned int)'0');
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return;
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}
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int is_neg = (d < 0);
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while (d != 0) {
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buf[size++] = '0' + d % 10;
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d /= 10;
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}
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if (is_neg)
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uart_send((unsigned int)'-');
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while (size--)
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uart_send(buf[size]);
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}
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