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   1 /*
   2  * Copyright © 2011 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include "ao.h"
  19 #include "ao_product.h"
  20
  21 static struct ao_companion_command      ao_companion_command;
  22 static const struct ao_companion_setup  ao_companion_setup = {
  23         .board_id               = AO_idProduct_NUMBER,
  24         .board_id_inverse       = ~AO_idProduct_NUMBER,
  25         .update_period          = 50,
  26         .channels               = NUM_ADC
  27 };
  28
  29 static uint8_t ao_spi_slave_recv(void)
  30 {
  31         uint8_t *buf;
  32         uint8_t len;
  33
  34         len = sizeof (ao_companion_command);
  35         buf = (uint8_t *) &ao_companion_command;
  36         while (len--) {
  37                 while (!(SPSR & (1 << SPIF)))
  38                         if ((PINB & (1 << PINB0)))
  39                                 return 0;
  40                 *buf++ = SPDR;
  41         }
  42
  43         /* Figure out the outbound data */
  44         switch (ao_companion_command.command) {
  45         case AO_COMPANION_SETUP:
  46                 buf = (uint8_t *) &ao_companion_setup;
  47                 len = sizeof (ao_companion_setup);
  48                 break;
  49         case AO_COMPANION_FETCH:
  50                 buf = (uint8_t *) &ao_adc_ring[ao_adc_ring_prev(ao_adc_head)].adc;
  51                 len = NUM_ADC * sizeof (uint16_t);
  52                 break;
  53         case AO_COMPANION_STATE:
  54                 break;
  55         default:
  56                 return 0;
  57         }
  58
  59         if (len) {
  60                 /* Send the outbound data */
  61                 while (len--) {
  62                         SPDR = *buf++;
  63                         while (!(SPSR & (1 << SPIF)))
  64                                 if ((PINB & (1 << PINB0)))
  65                                         return 0;
  66                 }
  67                 (void) SPDR;
  68         }
  69         ao_log_store.tm_tick = ao_companion_command.tick;
  70         if (ao_log_store.tm_state != ao_companion_command.flight_state) {
  71                 ao_log_store.tm_state = ao_companion_command.flight_state;
  72                 return 1;
  73         }
  74         return 0;
  75 }
  76
  77 static uint8_t ao_spi_slave_running;
  78
  79 ISR(PCINT0_vect)
  80 {
  81         if ((PINB & (1 << PINB0)) == 0) {
  82                 if (!ao_spi_slave_running) {
  83                         uint8_t changed;
  84                         ao_spi_slave_running = 1;
  85                         cli();
  86                         changed = ao_spi_slave_recv();
  87                         sei();
  88                         if (changed && ao_flight_boost <= ao_log_store.tm_state) {
  89                                 if (ao_log_store.tm_state < ao_flight_landed)
  90                                         ao_log_start();
  91                                 else
  92                                         ao_log_stop();
  93                         }
  94                 }
  95         } else {
  96                 ao_spi_slave_running = 0;
  97         }
  98 }
  99
 100 void ao_spi_slave_debug(void) {
 101         printf ("slave running %d\n", ao_spi_slave_running);
 102 }
 103
 104 void
 105 ao_spi_slave_init(void)
 106 {
 107         PCMSK0 |= (1 << PCINT0);        /* Enable PCINT0 pin change */
 108         PCICR |= (1 << PCIE0);          /* Enable pin change interrupt */
 109
 110         DDRB = (DDRB & 0xf0) | (1 << 3);
 111         SPCR = (0 << SPIE) |            /* Disable SPI interrupts */
 112                 (1 << SPE) |            /* Enable SPI */
 113                 (0 << DORD) |           /* MSB first */
 114                 (0 << MSTR) |           /* Slave mode */
 115                 (0 << CPOL) |           /* Clock low when idle */
 116                 (0 << CPHA);            /* Sample at leading clock edge */
 117 }