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/*
hc595.c
This defines a sample for a very simple "peripheral"
that can talk to an AVR core.
It is in fact a bit more involved than strictly necessary,
but is made to demonstrante a few useful features that are
easy to use.
Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
This file is part of simavr.
simavr is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
simavr is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with simavr. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include "sim_avr.h"
#include "hc595.h"
/*
* called when a SPI byte is sent
*/
static void hc595_spi_in_hook(struct avr_irq_t * irq, uint32_t value, void * param)
{
hc595_t * p = (hc595_t*)param;
// send "old value" to any chained one..
avr_raise_irq(p->irq + IRQ_HC595_SPI_BYTE_OUT, p->value);
p->value = (p->value << 8) | (value & 0xff);
}
/*
* called when a LATCH signal is sent
*/
static void hc595_latch_hook(struct avr_irq_t * irq, uint32_t value, void * param)
{
hc595_t * p = (hc595_t*)param;
if (irq->value && !value) { // falling edge
p->latch = p->value;
avr_raise_irq(p->irq + IRQ_HC595_OUT, p->latch);
}
}
/*
* called when a RESET signal is sent
*/
static void hc595_reset_hook(struct avr_irq_t * irq, uint32_t value, void * param)
{
hc595_t * p = (hc595_t*)param;
if (irq->value && !value) // falling edge
p->latch = p->value = 0;
}
static const char * irq_names[IRQ_HC595_COUNT] = {
[IRQ_HC595_SPI_BYTE_IN] = "8<hc595.in",
[IRQ_HC595_SPI_BYTE_OUT] = "8>hc595.chain",
[IRQ_HC595_IN_LATCH] = "<hc595.latch",
[IRQ_HC595_IN_RESET] = "<hc595.reset",
[IRQ_HC595_OUT] = "8>hc595.out",
};
void
hc595_init(
struct avr_t * avr,
hc595_t *p)
{
p->irq = avr_alloc_irq(&avr->irq_pool, 0, IRQ_HC595_COUNT, irq_names);
avr_irq_register_notify(p->irq + IRQ_HC595_SPI_BYTE_IN, hc595_spi_in_hook, p);
avr_irq_register_notify(p->irq + IRQ_HC595_IN_LATCH, hc595_latch_hook, p);
avr_irq_register_notify(p->irq + IRQ_HC595_IN_RESET, hc595_reset_hook, p);
p->latch = p->value = 0;
}
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