Add A/D sampler

[fw/altos] / ao_adc.c

diff --git a/ao_adc.c b/ao_adc.c
new file mode 100644 (file)
index 0000000..d45e10b
--- /dev/null
+++ b/ao_adc.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright © 2009 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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"
+
+__xdata struct ao_adc  ao_adc_ring[ADC_RING];
+__data uint8_t         ao_adc_head;
+
+void ao_adc_isr(void) interrupt 1
+{
+       uint8_t sequence;
+       uint8_t __xdata *a;
+       
+       sequence = (ADCCON2 & ADCCON2_SCH_MASK) >> ADCCON2_SCH_SHIFT;
+       a = (uint8_t __xdata *) (&ao_adc_ring[ao_adc_head].accel + sequence);
+       a[0] = ADCL;
+       a[1] = ADCH;
+       if (sequence < 5) {
+               /* start next channel conversion */
+               ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | (sequence + 1);
+       } else {
+               /* record this conversion series */
+               ao_adc_ring[ao_adc_head].tick = ao_time;
+               ao_adc_head++;
+               if (ao_adc_head == ADC_RING)
+                       ao_adc_head = 0;
+               ao_wakeup(ao_adc_ring);
+       }
+}
+
+void ao_adc_init(void)
+{
+       ADCCFG = ((1 << 0) |    /* acceleration */
+                 (1 << 1) |    /* pressure */
+                 (1 << 2) |    /* temperature */
+                 (1 << 3) |    /* battery voltage */
+                 (1 << 4) |    /* drogue sense */
+                 (1 << 5));    /* main sense */
+       
+       /* enable interrupts */
+       ADCIF = 0;
+       IEN0 |= IEN0_ADCIE;
+}
+
+void ao_adc_poll(void)
+{
+       ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | 0;
+}
+
+void ao_adc_get(__xdata struct ao_adc *packet)
+{
+       uint8_t i = ao_adc_head;
+       if (i == 0)
+               i = ADC_RING;
+       i--;
+       memcpy(packet, &ao_adc_ring[i], sizeof (struct ao_adc));
+}
+