134 lines
3.2 KiB
C
134 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_inited = 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_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_inited = 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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{
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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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{
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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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{
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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(uint64_t d)
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{
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unsigned int n;
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for (int 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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