cloudbase.mooo.com Git - z180-stamp.git/blame_incremental

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Commit	Line	Data
	1	/*
	2	* (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
	3	*
	4	* SPDX-License-Identifier: GPL-2.0+
	5	*/
	6
	7	#include <avr/io.h>
	8	#include <avr/interrupt.h>
	9	#include <util/atomic.h>
	10	#include <errno.h>
	11	#include <stdio.h>
	12
	13	#include "ring.h"
	14	#include "serial.h"
	15
	16
	17	static int _write(char c, FILE *stream);
	18	static FILE mystdout = FDEV_SETUP_STREAM(_write,
	19	NULL, _FDEV_SETUP_WRITE);
	20
	21
	22
	23	#define BUFFER_SIZE 128
	24
	25	#if ((BUFFER_SIZE-1) & BUFFER_SIZE)
	26	# error: BUFFER_SIZE not power of 2
	27	#endif
	28
	29	#if ((BUFFER_SIZE) > 256)
	30	# error: BUFFER_SIZE
	31	#endif
	32
	33	struct ring rx_ring;
	34	struct ring tx_ring;
	35	uint8_t rx_ring_buffer[BUFFER_SIZE];
	36	uint8_t tx_ring_buffer[BUFFER_SIZE];
	37
	38
	39
	40	/* Initialize UART */
	41
	42	void usart0_setup(unsigned long baud) {
	43
	44	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
	45
	46	PRR0 &= ~_BV(PRUSART0);
	47	UCSR0B = 0;
	48	UCSR0A = 0;
	49	UBRR0 = (F_CPU + (baud/2) + 8) / baud / 16 - 1;
	50	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0);
	51	UCSR0C = 3 << UCSZ00;
	52
	53	/* Initialize ring buffers. */
	54	ring_init(&rx_ring, rx_ring_buffer, BUFFER_SIZE);
	55	ring_init(&tx_ring, tx_ring_buffer, BUFFER_SIZE);
	56	};
	57	}
	58
	59	/--------------------------------------------------------------------------/
	60
	61	/* UART RXC interrupt */
	62
	63	ISR(USART0_RX_vect)
	64	{
	65	uint8_t d;
	66
	67	d = UDR0;
	68	ring_write_ch(&rx_ring, d);
	69	}
	70
	71	/* UART UDRE interrupt */
	72
	73	ISR(USART0_UDRE_vect)
	74	{
	75	int d = ring_read_ch(&tx_ring);
	76
	77	if (d < 0) {
	78	/* Disable TX empty interrupt. */
	79	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0);
	80	} else {
	81	UDR0 = d;
	82	}
	83	}
	84
	85	/--------------------------------------------------------------------------/
	86
	87	void serial_setup(unsigned long baud)
	88	{
	89	stdout = &mystdout;
	90	usart0_setup(baud);
	91	}
	92
	93	/--------------------------------------------------------------------------/
	94
	95	int _write(char c, FILE *stream)
	96	{
	97	(void) stream;
	98
	99	if (c == '\n')
	100	serial_putc('\r');
	101	serial_putc(c);
	102
	103	return 0;
	104	}
	105
	106	int serial_getc(void)
	107	{
	108	return ring_read_ch(&rx_ring);
	109	}
	110
	111	void serial_putc(char data)
	112	{
	113	while (ring_write_ch(&tx_ring, data) < 0)
	114	;
	115
	116	/* Enable the TXE interrupt. */
	117	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0) \| _BV(UDRIE0);
	118	}
	119
	120	uint_fast8_t serial_tstc(void)
	121	{
	122	return !ring_is_empty(&rx_ring);
	123	}