altos: Integrate telescience support

[fw/altos] / src / avr / ao_spi_slave.c

diff --git a/src/avr/ao_spi_slave.c b/src/avr/ao_spi_slave.c
new file mode 100644 (file)
index 0000000..4dde09f
--- /dev/null
+++ b/src/avr/ao_spi_slave.c
@@ -0,0 +1,142 @@
+/*
+ * 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 */
+}