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/*
* 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_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 character 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++);
}
}
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