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-rw-r--r--src/ao.h10
-rw-r--r--src/ao_adc.c38
-rw-r--r--src/ao_config.c6
-rw-r--r--src/ao_flight.c95
-rw-r--r--src/ao_flight_test.c4
-rw-r--r--src/ao_ignite.c1
-rw-r--r--src/ao_log.c4
-rw-r--r--src/ao_pins.h3
-rw-r--r--src/ao_test.c2
9 files changed, 136 insertions, 27 deletions
diff --git a/src/ao.h b/src/ao.h
index 5721c344..cef20e61 100644
--- a/src/ao.h
+++ b/src/ao.h
@@ -163,6 +163,11 @@ struct ao_adc {
#endif
#if HAS_ADC
+
+#ifndef HAS_ACCEL_REF
+#error Please define HAS_ACCEL_REF
+#endif
+
/*
* ao_adc.c
*/
@@ -178,6 +183,9 @@ struct ao_adc {
*/
extern volatile __xdata struct ao_adc ao_adc_ring[AO_ADC_RING];
extern volatile __data uint8_t ao_adc_head;
+#if HAS_ACCEL_REF
+extern volatile __xdata uint16_t ao_accel_ref[AO_ADC_RING];
+#endif
/* Trigger a conversion sequence (called from the timer interrupt) */
void
@@ -649,7 +657,7 @@ enum ao_flight_state {
ao_flight_invalid = 9
};
-extern __xdata struct ao_adc ao_flight_data;
+extern __data uint8_t ao_flight_adc;
extern __pdata enum ao_flight_state ao_flight_state;
extern __pdata uint16_t ao_flight_tick;
extern __pdata int16_t ao_flight_accel;
diff --git a/src/ao_adc.c b/src/ao_adc.c
index 49d2519e..3adf9b2e 100644
--- a/src/ao_adc.c
+++ b/src/ao_adc.c
@@ -19,24 +19,25 @@
#include "ao_pins.h"
volatile __xdata struct ao_adc ao_adc_ring[AO_ADC_RING];
+#if HAS_ACCEL_REF
+volatile __xdata uint16_t ao_accel_ref[AO_ADC_RING];
+#endif
volatile __data uint8_t ao_adc_head;
void
ao_adc_poll(void)
{
+#if HAS_ACCEL_REF
+ ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | 2;
+#else
ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | 0;
-}
-
-void
-ao_adc_sleep(void)
-{
- ao_sleep(&ao_adc_ring);
+#endif
}
void
ao_adc_get(__xdata struct ao_adc *packet)
{
- uint8_t i = ao_adc_ring_prev(ao_adc_head);
+ uint8_t i = ao_adc_ring_prev(ao_flight_adc);
memcpy(packet, &ao_adc_ring[i], sizeof (struct ao_adc));
}
@@ -47,25 +48,34 @@ ao_adc_isr(void) __interrupt 1
uint8_t __xdata *a;
sequence = (ADCCON2 & ADCCON2_SCH_MASK) >> ADCCON2_SCH_SHIFT;
- if (sequence == ADCCON3_ECH_TEMP)
- sequence = 2;
- a = (uint8_t __xdata *) (&ao_adc_ring[ao_adc_head].accel + sequence);
+#if HAS_ACCEL_REF
+ if (sequence == 2) {
+ a = (uint8_t __xdata *) (&ao_accel_ref[ao_adc_head]);
+ sequence = 0;
+ } else
+#endif
+ {
+ if (sequence == ADCCON3_ECH_TEMP)
+ sequence = 2;
+ a = (uint8_t __xdata *) (&ao_adc_ring[ao_adc_head].accel + sequence);
+ sequence++;
+ }
a[0] = ADCL;
a[1] = ADCH;
- if (sequence < 5) {
+ if (sequence < 6) {
#if HAS_EXTERNAL_TEMP == 0
/* start next channel conversion */
/* v0.2 replaces external temp sensor with internal one */
- if (sequence == 1)
+ if (sequence == 2)
ADCCON3 = ADCCON3_EREF_1_25 | ADCCON3_EDIV_512 | ADCCON3_ECH_TEMP;
else
#endif
- ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | (sequence + 1);
+ ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | sequence;
} else {
/* record this conversion series */
ao_adc_ring[ao_adc_head].tick = ao_time();
ao_adc_head = ao_adc_ring_next(ao_adc_head);
- ao_wakeup(ao_adc_ring);
+ ao_wakeup(DATA_TO_XDATA(&ao_adc_head));
}
}
diff --git a/src/ao_config.c b/src/ao_config.c
index e97b7eb1..bbee3b44 100644
--- a/src/ao_config.c
+++ b/src/ao_config.c
@@ -209,10 +209,10 @@ ao_config_accel_calibrate_auto(char *orientation) __reentrant
puts("Calibrating..."); flush();
i = ACCEL_CALIBRATE_SAMPLES;
accel_total = 0;
- cal_adc_ring = ao_adc_head;
+ cal_adc_ring = ao_flight_adc;
while (i) {
- ao_sleep(&ao_adc_ring);
- while (i && cal_adc_ring != ao_adc_head) {
+ ao_sleep(DATA_TO_XDATA(&ao_flight_adc));
+ while (i && cal_adc_ring != ao_flight_adc) {
accel_total += (int32_t) ao_adc_ring[cal_adc_ring].accel;
cal_adc_ring = ao_adc_ring_next(cal_adc_ring);
i--;
diff --git a/src/ao_flight.c b/src/ao_flight.c
index e99692a3..81aecad3 100644
--- a/src/ao_flight.c
+++ b/src/ao_flight.c
@@ -146,16 +146,103 @@ ao_flight(void)
ao_raw_pres = 0;
ao_flight_tick = 0;
for (;;) {
- ao_sleep(&ao_adc_ring);
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_adc));
+ ao_sleep(DATA_TO_XDATA(&ao_adc_head));
while (ao_flight_adc != ao_adc_head) {
__pdata uint8_t ticks;
__pdata int16_t ao_vel_change;
+ __xdata struct ao_adc *ao_adc;
ao_flight_prev_tick = ao_flight_tick;
/* Capture a sample */
- ao_raw_accel = ao_adc_ring[ao_flight_adc].accel;
- ao_raw_pres = ao_adc_ring[ao_flight_adc].pres;
- ao_flight_tick = ao_adc_ring[ao_flight_adc].tick;
+ ao_adc = &ao_adc_ring[ao_flight_adc];
+ ao_flight_tick = ao_adc->tick;
+ ao_raw_accel = ao_adc->accel;
+#if HAS_ACCEL_REF
+ /*
+ * Ok, the math here is a bit tricky.
+ *
+ * ao_raw_accel: ADC output for acceleration
+ * ao_accel_ref: ADC output for the 5V reference.
+ * ao_cook_accel: Corrected acceleration value
+ * Vcc: 3.3V supply to the CC1111
+ * Vac: 5V supply to the accelerometer
+ * accel: input voltage to accelerometer ADC pin
+ * ref: input voltage to 5V reference ADC pin
+ *
+ *
+ * Measured acceleration is ratiometric to Vcc:
+ *
+ * ao_raw_accel accel
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ * Measured 5v reference is also ratiometric to Vcc:
+ *
+ * ao_accel_ref ref
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ *
+ * ao_accel_ref = 32767 * (ref / Vcc)
+ *
+ * Acceleration is measured ratiometric to the 5V supply,
+ * so what we want is:
+ *
+ * ao_cook_accel accel
+ * ------------- = -----
+ * 32767 ref
+ *
+ *
+ * accel Vcc
+ * = ----- * ---
+ * Vcc ref
+ *
+ * ao_raw_accel 32767
+ * = ------------ * ------------
+ * 32737 ao_accel_ref
+ *
+ * Multiply through by 32767:
+ *
+ * ao_raw_accel * 32767
+ * ao_cook_accel = --------------------
+ * ao_accel_ref
+ *
+ * Now, the tricky part. Getting this to compile efficiently
+ * and keeping all of the values in-range.
+ *
+ * First off, we need to use a shift of 16 instead of * 32767 as SDCC
+ * does the obvious optimizations for byte-granularity shifts:
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / ao_accel_ref
+ *
+ * Next, lets check our input ranges:
+ *
+ * 0 <= ao_raw_accel <= 0x7fff (singled ended ADC conversion)
+ * 0x7000 <= ao_accel_ref <= 0x7fff (the 5V ref value is close to 0x7fff)
+ *
+ * Plugging in our input ranges, we get an output range of 0 - 0x12490,
+ * which is 17 bits. That won't work. If we take the accel ref and shift
+ * by a bit, we'll change its range:
+ *
+ * 0xe000 <= ao_accel_ref<<1 <= 0xfffe
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / (ao_accel_ref << 1)
+ *
+ * Now the output range is 0 - 0x9248, which nicely fits in 16 bits. It
+ * is, however, one bit too large for our signed computations. So, we
+ * take the result and shift that by a bit:
+ *
+ * ao_cook_accel = ((ao_raw_accel << 16) / (ao_accel_ref << 1)) >> 1
+ *
+ * This finally creates an output range of 0 - 0x4924. As the ADC only
+ * provides 11 bits of data, we haven't actually lost any precision,
+ * just dropped a bit of noise off the low end.
+ */
+ ao_raw_accel = (uint16_t) ((((uint32_t) ao_raw_accel << 16) / (ao_accel_ref[ao_flight_adc] << 1))) >> 1;
+ ao_adc->accel = ao_raw_accel;
+#endif
+ ao_raw_pres = ao_adc->pres;
ao_flight_accel -= ao_flight_accel >> 4;
ao_flight_accel += ao_raw_accel >> 4;
diff --git a/src/ao_flight_test.c b/src/ao_flight_test.c
index e0cfa47a..5c619518 100644
--- a/src/ao_flight_test.c
+++ b/src/ao_flight_test.c
@@ -180,7 +180,7 @@ void
ao_sleep(void *wchan)
{
ao_dump_state();
- if (wchan == &ao_adc_ring) {
+ if (wchan == &ao_adc_head) {
char type;
uint16_t tick;
uint16_t a, b;
@@ -238,6 +238,8 @@ ao_sleep(void *wchan)
switch (type) {
case 'F':
ao_flight_ground_accel = a;
+ ao_config.accel_plus_g = a;
+ ao_config.accel_minus_g = a + 530;
ao_flight_started = 1;
break;
case 'S':
diff --git a/src/ao_ignite.c b/src/ao_ignite.c
index f2b15dd2..603fcd25 100644
--- a/src/ao_ignite.c
+++ b/src/ao_ignite.c
@@ -52,7 +52,6 @@ ao_igniter_status(enum ao_igniter igniter)
__xdata uint8_t request, firing, fired;
__critical {
- ao_adc_sleep();
ao_adc_get(&adc);
request = ao_ignition[igniter].request;
fired = ao_ignition[igniter].fired;
diff --git a/src/ao_log.c b/src/ao_log.c
index fa072550..099c5f6f 100644
--- a/src/ao_log.c
+++ b/src/ao_log.c
@@ -99,10 +99,10 @@ ao_log(void)
/* Write the whole contents of the ring to the log
* when starting up.
*/
- ao_log_adc_pos = ao_adc_ring_next(ao_adc_head);
+ ao_log_adc_pos = ao_adc_ring_next(ao_flight_adc);
for (;;) {
/* Write samples to EEPROM */
- while (ao_log_adc_pos != ao_adc_head) {
+ while (ao_log_adc_pos != ao_flight_adc) {
log.type = AO_LOG_SENSOR;
log.tick = ao_adc_ring[ao_log_adc_pos].tick;
log.u.sensor.accel = ao_adc_ring[ao_log_adc_pos].accel;
diff --git a/src/ao_pins.h b/src/ao_pins.h
index 9446964e..2c5b9db5 100644
--- a/src/ao_pins.h
+++ b/src/ao_pins.h
@@ -31,6 +31,7 @@
#define AO_LED_RED 1
#define LEDS_AVAILABLE (AO_LED_RED)
#define HAS_EXTERNAL_TEMP 0
+ #define HAS_ACCEL_REF 0
#endif
#if defined(TELEMETRUM_V_1_1)
@@ -46,6 +47,7 @@
#define AO_LED_RED 1
#define LEDS_AVAILABLE (AO_LED_RED)
#define HAS_EXTERNAL_TEMP 0
+ #define HAS_ACCEL_REF 1
#define SPI_CS_ON_P1 1
#define SPI_CS_ON_P0 0
#define M25_CS_MASK 0x02 /* CS0 is P1_1 */
@@ -81,6 +83,7 @@
#define AO_LED_GREEN 1
#define LEDS_AVAILABLE (AO_LED_RED|AO_LED_GREEN)
#define HAS_EXTERNAL_TEMP 1
+ #define HAS_ACCEL_REF 0
#define SPI_CS_ON_P1 1
#define SPI_CS_ON_P0 0
#endif
diff --git a/src/ao_test.c b/src/ao_test.c
index b9f7d338..14c2eb75 100644
--- a/src/ao_test.c
+++ b/src/ao_test.c
@@ -53,7 +53,7 @@ blink_1(void)
static __xdata struct ao_adc adc;
for (;;) {
- ao_sleep(&ao_adc_ring);
+ ao_sleep(&ao_adc_head);
ao_adc_get(&adc);
if (adc.accel < 15900)
ao_led_on(AO_LED_RED);
generated by cgit v1.2.3 (git 2.39.1) at 2025-10-31 07:33:10 +0000