You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
105 lines
3.5 KiB
C
105 lines
3.5 KiB
C
/*
|
|
* Copyright (C) 2018 bzt (bztsrc@github)
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person
|
|
* obtaining a copy of this software and associated documentation
|
|
* files (the "Software"), to deal in the Software without
|
|
* restriction, including without limitation the rights to use, copy,
|
|
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
|
* of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be
|
|
* included in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
|
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
|
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
|
* DEALINGS IN THE SOFTWARE.
|
|
*
|
|
*/
|
|
|
|
#include "gpio.h"
|
|
|
|
/* Auxilary mini UART registers */
|
|
#define AUX_ENABLE ((volatile unsigned int*)(MMIO_BASE+0x00215004))
|
|
#define AUX_MU_IO ((volatile unsigned int*)(MMIO_BASE+0x00215040))
|
|
#define AUX_MU_IER ((volatile unsigned int*)(MMIO_BASE+0x00215044))
|
|
#define AUX_MU_IIR ((volatile unsigned int*)(MMIO_BASE+0x00215048))
|
|
#define AUX_MU_LCR ((volatile unsigned int*)(MMIO_BASE+0x0021504C))
|
|
#define AUX_MU_MCR ((volatile unsigned int*)(MMIO_BASE+0x00215050))
|
|
#define AUX_MU_LSR ((volatile unsigned int*)(MMIO_BASE+0x00215054))
|
|
#define AUX_MU_MSR ((volatile unsigned int*)(MMIO_BASE+0x00215058))
|
|
#define AUX_MU_SCRATCH ((volatile unsigned int*)(MMIO_BASE+0x0021505C))
|
|
#define AUX_MU_CNTL ((volatile unsigned int*)(MMIO_BASE+0x00215060))
|
|
#define AUX_MU_STAT ((volatile unsigned int*)(MMIO_BASE+0x00215064))
|
|
#define AUX_MU_BAUD ((volatile unsigned int*)(MMIO_BASE+0x00215068))
|
|
|
|
/**
|
|
* Set baud rate and characteristics (115200 8N1) and map to GPIO
|
|
*/
|
|
void uart_init()
|
|
{
|
|
register unsigned int r;
|
|
|
|
/* initialize UART */
|
|
*AUX_ENABLE |=1; // enable UART1, AUX mini uart
|
|
*AUX_MU_IER = 0;
|
|
*AUX_MU_CNTL = 0;
|
|
*AUX_MU_LCR = 3; // 8 bits
|
|
*AUX_MU_MCR = 0;
|
|
*AUX_MU_IER = 0;
|
|
*AUX_MU_IIR = 0xc6; // disable interrupts
|
|
*AUX_MU_BAUD = 270; // 115200 baud
|
|
/* map UART1 to GPIO pins */
|
|
r=*GPFSEL1;
|
|
r&=~((7<<12)|(7<<15)); // gpio14, gpio15
|
|
r|=(2<<12)|(2<<15); // alt5
|
|
*GPFSEL1 = r;
|
|
*GPPUD = 0; // enable pins 14 and 15
|
|
r=150; while(r--) { asm volatile("nop"); }
|
|
*GPPUDCLK0 = (1<<14)|(1<<15);
|
|
r=150; while(r--) { asm volatile("nop"); }
|
|
*GPPUDCLK0 = 0; // flush GPIO setup
|
|
*AUX_MU_CNTL = 3; // enable Tx, Rx
|
|
}
|
|
|
|
/**
|
|
* Send a character
|
|
*/
|
|
void uart_send(unsigned int c) {
|
|
/* wait until we can send */
|
|
do{asm volatile("nop");}while(!(*AUX_MU_LSR&0x20));
|
|
/* write the carachter to the buffer */
|
|
*AUX_MU_IO=c;
|
|
}
|
|
|
|
/**
|
|
* Receive a character
|
|
*/
|
|
char uart_getc() {
|
|
char r;
|
|
/* wait until something is in the buffer */
|
|
do{asm volatile("nop");}while(!(*AUX_MU_LSR&0x01));
|
|
/* read it and return */
|
|
r=(char)(*AUX_MU_IO);
|
|
/* convert carrige return to newline */
|
|
return r=='\r'?'\n':r;
|
|
}
|
|
|
|
/**
|
|
* Display a string
|
|
*/
|
|
void uart_puts(char *s) {
|
|
while(*s) {
|
|
/* convert newline to carrige return + newline */
|
|
if(*s=='\n')
|
|
uart_send('\r');
|
|
uart_send(*s++);
|
|
}
|
|
}
|