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

... / ...

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
	49	/* Initialize ring buffers. */
	50	ring_init(&rx_ring, rx_ring_buffer, BUFFER_SIZE);
	51	ring_init(&tx_ring, tx_ring_buffer, BUFFER_SIZE);
	52
	53	UCSR0A = 0;
	54	UBRR0 = F_CPU / baud / 16 - 1;
	55	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0);
	56	UCSR0C = 3 << UCSZ00;
	57	};
	58	}
	59
	60	/--------------------------------------------------------------------------/
	61
	62	/* UART RXC interrupt */
	63
	64	ISR(USART0_RX_vect)
	65	{
	66	uint8_t d;
	67
	68	d = UDR0;
	69	ring_write_ch(&rx_ring, d);
	70	}
	71
	72	/* UART UDRE interrupt */
	73
	74	ISR(USART0_UDRE_vect)
	75	{
	76	int d = ring_read_ch(&tx_ring);
	77
	78	if (d < 0) {
	79	/* Disable TX empty interrupt. */
	80	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0);
	81	} else {
	82	UDR0 = d;
	83	}
	84	}
	85
	86	/--------------------------------------------------------------------------/
	87
	88	void serial_setup(unsigned long baud)
	89	{
	90	stdout = &mystdout;
	91	usart0_setup(baud);
	92	}
	93
	94	/--------------------------------------------------------------------------/
	95
	96	int _write(char c, FILE *stream)
	97	{
	98	(void) stream;
	99
	100	if (c == '\n')
	101	serial_putc('\r');
	102	serial_putc(c);
	103
	104	return 0;
	105	}
	106
	107	int serial_getc(void)
	108	{
	109	return ring_read_ch(&rx_ring);
	110	}
	111
	112	void serial_putc(char data)
	113	{
	114	while (ring_write_ch(&tx_ring, data) < 0)
	115	;
	116
	117	/* Enable the TXE interrupt. */
	118	UCSR0B = _BV(RXCIE0) \| _BV(RXEN0) \| _BV(TXEN0) \| _BV(UDRIE0);
	119	}
	120
	121	uint_fast8_t serial_tstc(void)
	122	{
	123	return !ring_is_empty(&rx_ring);
	124	}