+/*
+ * 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 */
+}