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/*
* Copyright © 2011 Keith Packard <keithp@keithp.com>
*
* This program 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; version 2 of the License.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include "ao.h"
#include "ao_product.h"
struct ao_companion_command ao_companion_command;
static const struct ao_companion_setup ao_telescience_setup = {
.board_id = AO_idProduct_NUMBER,
.board_id_inverse = ~AO_idProduct_NUMBER,
.update_period = 50,
.channels = AO_LOG_TELESCIENCE_NUM_ADC,
};
static uint8_t
ao_spi_read(uint8_t *buf, uint8_t len)
{
while (len--) {
while (!(SPSR & (1 << SPIF)))
if ((PINB & (1 << PINB0)))
return 0;
*buf++ = SPDR;
}
return 1;
}
static void
ao_spi_write(uint8_t *buf, uint8_t len)
{
while (len--) {
SPDR = *buf++;
while (!(SPSR & (1 << SPIF)))
if ((PINB & (1 << PINB0)))
return;
}
/* Clear pending SPIF bit by reading */
(void) SPDR;
}
static uint8_t ao_spi_slave_recv(void)
{
if (!ao_spi_read((uint8_t *) &ao_companion_command,
sizeof (ao_companion_command)))
return 0;
/* Figure out the outbound data */
switch (ao_companion_command.command) {
case AO_COMPANION_SETUP:
ao_spi_write((uint8_t *) &ao_telescience_setup,
sizeof (ao_telescience_setup));
break;
case AO_COMPANION_FETCH:
ao_spi_write((uint8_t *) &ao_adc_ring[ao_adc_ring_prev(ao_adc_head)].adc,
AO_LOG_TELESCIENCE_NUM_ADC * sizeof (uint16_t));
break;
case AO_COMPANION_NOTIFY:
break;
default:
return 0;
}
ao_log_store.tm_tick = ao_companion_command.tick;
if (ao_log_store.tm_state != ao_companion_command.flight_state) {
ao_log_store.tm_state = ao_companion_command.flight_state;
return 1;
}
return 0;
}
static uint8_t ao_spi_slave_running;
ISR(PCINT0_vect)
{
if ((PINB & (1 << PINB0)) == 0) {
if (!ao_spi_slave_running) {
uint8_t changed;
ao_spi_slave_running = 1;
cli();
changed = ao_spi_slave_recv();
sei();
if (changed && ao_flight_boost <= ao_log_store.tm_state) {
if (ao_log_store.tm_state < ao_flight_landed)
ao_log_start();
else
ao_log_stop();
}
}
} else {
ao_spi_slave_running = 0;
}
}
void ao_spi_slave_debug(void) {
printf ("slave running %d\n", ao_spi_slave_running);
}
void
ao_spi_slave_init(void)
{
PCMSK0 |= (1 << PCINT0); /* Enable PCINT0 pin change */
PCICR |= (1 << PCIE0); /* Enable pin change interrupt */
DDRB = ((DDRB & 0xf0) |
(1 << 3) | /* MISO, output */
(0 << 2) | /* MOSI, input */
(0 << 1) | /* SCK, input */
(0 << 0)); /* SS, input */
/* We'd like to have a pull-up on SS so that disconnecting the
* TM would cause any SPI transaction to abort. However, when
* I tried that, SPI transactions would spontaneously abort,
* making me assume that we needed a less aggressive pull-up
* than is offered inside the AVR
*/
PORTB = ((PORTB & 0xf0) |
(1 << 3) | /* MISO, output */
(0 << 2) | /* MOSI, no pull-up */
(0 << 1) | /* SCK, no pull-up */
(0 << 0)); /* SS, no pull-up */
SPCR = (0 << SPIE) | /* Disable SPI interrupts */
(1 << SPE) | /* Enable SPI */
(0 << DORD) | /* MSB first */
(0 << MSTR) | /* Slave mode */
(0 << CPOL) | /* Clock low when idle */
(0 << CPHA); /* Sample at leading clock edge */
}
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