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git://projects.qi-hardware.com/f32xbase.git
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126 lines
2.1 KiB
C
126 lines
2.1 KiB
C
/*
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* common/uart.c - UART initialization and debug output
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*
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* Written 2008, 2009 by Werner Almesberger
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* Copyright 2008, 2009 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdarg.h>
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#include <stdio.h>
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#include "regs.h"
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#include "uart.h"
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/* gpio j4=0 */
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#ifndef CONFIG_USB_PUTCHAR
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void putchar(char c)
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{
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if (c == '\n')
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putchar('\r');
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SBUF0 = c;
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while (!TI0);
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TI0 = 0;
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}
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#endif /* !CONFIG_USB_PUTCHAR */
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/* for now, we always use printf_tiny, which doesn't have a vprintf* version */
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#ifdef noCONFIG_PRINTK
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void printk(const char *fmt, ...)
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{
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va_list ap;
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__bit saved;
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va_start(ap, fmt);
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saved = EA;
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EA = 0;
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vprintf(fmt, ap);
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EA = saved;
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va_end(ap);
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}
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#endif /* CONFIG_PRINTK */
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void uart_init(uint8_t brg_mhz)
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{
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/*
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* UART: Enable only transmitter, no interrupts.
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*/
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SCON0 = 0; /* also clears TI0 */
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SMOD0 = S0DL1 | S0DL0;
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/*
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* Configure the UART to 115200bps, see table 13.1
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*
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* We can's support 1.5MHz (that is, without using the USB clock, but
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* why would one want to run the core at 1.5MHz when USB is around ?)
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*
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* The closes settings would be:
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*
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* SBRL0 = 0xfff9; -- 107142.9 bps, error = -7%
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* SBRL0 = 0xfffa; -- 125000 bps, error = +8.5%
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*
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* Depending on signal quality, we would need something like +/-5%.
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*/
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#if defined(UART_115200_BPS)
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switch (brg_mhz) {
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case 3:
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SBRL0 = 0xfff3;
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break;
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case 6:
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SBRL0 = 0xffe6;
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break;
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case 12:
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SBRL0 = 0xffcc;
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break;
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case 24:
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SBRL0 = 0xff98;
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break;
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case 48:
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SBRL0 = 0xff30;
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break;
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}
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#elif defined(UART_57600_BPS)
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switch (brg_mhz) {
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case 3:
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SBRL0 = 0xffe6;
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break;
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case 6:
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SBRL0 = 0xffcc;
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break;
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case 12:
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SBRL0 = 0xff98;
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break;
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case 24:
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SBRL0 = 0xff30;
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break;
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case 48:
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SBRL0 = 0xfe5f;
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break;
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}
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#else
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#error "must set either UART_115200_BPS or UART_57600_BPS"
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#endif
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SBCON0 = SB0RUN | SB0PS0 | SB0PS1;
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/*
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* Make TX a push-pull output
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*/
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P0MDOUT |= 1 << 4;
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}
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