nes-proj/cpu/rl78/uart0.c

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/*
* Copyright (c) 2014, Analog Devices, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \author Maxim Salov <max.salov@gmail.com>, Ian Martin <martini@redwirellc.com>
*/
#include "rl78.h" /* for f_CLK */
#include "sfrs.h"
#include "sfrs-ext.h"
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#include "uart0.h"
#define DESIRED_BAUDRATE 38400
/* Note that only 9600, 38400, and 115200 bps were tested. */
#define PRESCALE_THRESH ((38400 + 115200) / 2)
#define PRS_VALUE ((DESIRED_BAUDRATE < PRESCALE_THRESH) ? 4 : 0)
#define f_MCK (f_CLK / (1 << PRS_VALUE))
#define SDR_VALUE (f_MCK / DESIRED_BAUDRATE / 2 - 1)
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void
uart0_init(void)
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{
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/* Reference R01AN0459EJ0100 or hardware manual for details */
PIOR = 0U; /* Disable IO redirection */
PM1 |= 0x06U; /* Set P11 and P12 as inputs */
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SAU0EN = 1; /* Supply clock to serial array unit 0 */
SPS0 = (PRS_VALUE << 4) | PRS_VALUE; /* Set input clock (CK00 and CK01) to fclk/16 = 2MHz */
ST0 = 0x03U; /* Stop operation of channel 0 and 1 */
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/* Setup interrupts (disable) */
STMK0 = 1; /* Disable INTST0 interrupt */
STIF0 = 0; /* Clear INTST0 interrupt request flag */
STPR10 = 1; /* Set INTST0 priority: lowest */
STPR00 = 1;
SRMK0 = 1; /* Disable INTSR0 interrupt */
SRIF0 = 0; /* Clear INTSR0 interrupt request flag */
SRPR10 = 1; /* Set INTSR0 priority: lowest */
SRPR00 = 1;
SREMK0 = 1; /* Disable INTSRE0 interrupt */
SREIF0 = 0; /* Clear INTSRE0 interrupt request flag */
SREPR10 = 1; /* Set INTSRE0 priority: lowest */
SREPR00 = 1;
/* Setup operation mode for transmitter (channel 0) */
SMR00 = 0x0023U; /* Operation clock : CK00,
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Transfer clock : division of CK00
Start trigger : software
Detect falling edge as start bit
Operation mode : UART
Interrupt source : buffer empty
*/
SCR00 = 0x8097U; /* Transmission only
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Reception error interrupt masked
Phase clock : type 1
No parity
LSB first
1 stop bit
8-bit data length
*/
SDR00 = SDR_VALUE << 9;
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/* Setup operation mode for receiver (channel 1) */
NFEN0 |= 1; /* Enable noise filter on RxD0 pin */
SIR01 = 0x0007U; /* Clear error flags */
SMR01 = 0x0122U; /* Operation clock : CK00
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Transfer clock : division of CK00
Start trigger : valid edge on RxD pin
Detect falling edge as start bit
Operation mode : UART
Interrupt source : transfer end
*/
SCR01 = 0x4097U; /* Reception only
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Reception error interrupt masked
Phase clock : type 1
No parity
LSB first
1 stop bit
8-bit data length
*/
SDR01 = SDR_VALUE << 9;
SO0 |= 1; /* Prepare for use of channel 0 */
SOE0 |= 1;
P1 |= (1 << 2); /* Set TxD0 high */
PM1 &= ~(1 << 2); /* Set output mode for TxD0 */
PM1 |= (1 << 1); /* Set input mode for RxD0 */
SS0 |= 0x03U; /* Enable UART0 operation (both channels) */
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STIF0 = 1; /* Set buffer empty interrupt request flag */
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}
void
uart0_putchar(int c)
{
while(0 == STIF0) ;
STIF0 = 0;
SDR00 = c;
}
char
uart0_getchar(void)
{
char c;
while(!uart0_can_getchar()) ;
c = SDR01;
SRIF0 = 0;
return c;
}
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int
uart0_puts(const char *s)
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{
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int len = 0;
SMR00 |= 0x0001U; /* Set buffer empty interrupt */
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while('\0' != *s) {
uart0_putchar(*s);
s++;
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++len;
}
#if 0
while(0 == STIF0) ;
STIF0 = 0;
SDR00.sdr00 = '\r';
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#endif
SMR00 &= ~0x0001U;
uart0_putchar('\n');
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#if 0
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while(0 != SSR00.BIT.bit6) ; /* Wait until TSF00 == 0 */
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#endif
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return len;
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}