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rc filtering

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This commit is contained in:
Olaf Rempel 2008-02-04 18:19:25 +01:00
parent 508ab7c94b
commit 26b594582f
5 changed files with 168 additions and 58 deletions
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10
include/at91_tc1.h
View File

@ -3,12 +3,16 @@
#define MAX_CHANNELS 8
#define RC_CAL_START 0
#define RC_CAL_END 1
struct rc_values {
int16_t ch[MAX_CHANNELS];
uint32_t count;
int16_t chan[MAX_CHANNELS];
};
uint32_t rcontrol_getvalues(struct rc_values *rc);
void rcontrol_calibrate(uint32_t mode);
void at91_tc1_init(void);
uint32_t rc_ppm_getvalues(struct rc_values *rc);
#endif /*RC_PPM_H_*/

29
main.c
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@ -32,37 +32,27 @@
#include <stdio.h>
#include <string.h>
AT91S_AIC *aic = AT91C_BASE_AIC;
AT91S_TWI *twi = AT91C_BASE_TWI;
AT91S_UDP *udp = AT91C_BASE_UDP;
static uint32_t pitc_test(struct pitc_timer *timer)
{
static uint32_t i;
*AT91C_PIOA_SODR = i;
i = i ^ LED_GREEN;
*AT91C_PIOA_CODR = i;
/*
struct rc_values rc;
uint32_t valid = rc_ppm_getvalues(&rc);
if (!valid)
rc.count = 0;
printf("%d channels: ", rc.count);
struct rc_values rc;
uint32_t count = rcontrol_getvalues(&rc);
printf("%ld channels: ", count);
uint32_t j;
for (j = 0; j < rc.count; j++)
printf("%+3d ", rc.ch[j]);
for (j = 0; j < count; j++)
printf("%+4d ", rc.chan[j]);
printf("\n\r");
*/
return 0;
return PITC_RESTART_TIMER;
}
int main(void)
{
/* trigger pinchange-isrs */
at91_pio_init();
/* LED outputs */
*AT91C_PIOA_PER = LED_GREEN | LED_ORANGE;
*AT91C_PIOA_OER = LED_GREEN | LED_ORANGE;
@ -73,6 +63,9 @@ int main(void)
at91_dbgu_init();
at91_dbgu_puts("==========================================================\n\rGood morning Dave\n\r");
/* triggers pinchange-isrs */
at91_pio_init();
/* timer */
at91_pitc_init();
at91_rttc_test_init();
@ -87,7 +80,7 @@ int main(void)
/* usb */
at91_udp_init();
struct pitc_timer *pitc_test_timer = alloc_pitc_timer(10, &pitc_test, NULL);
struct pitc_timer *pitc_test_timer = alloc_pitc_timer(1, &pitc_test, NULL);
pitc_schedule_timer(pitc_test_timer);
printf("static alloc: %5ld bytes\n\r", static_alloc_used());

175
src/at91_tc1.c
View File

@ -18,70 +18,167 @@
***************************************************************************/
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h> /* abs() */
#include "AT91SAM7S256.h"
#include "board.h"
#include "at91_tc1.h"
#include "at91_pio.h"
/* Hard limits for ISR */
#define PULSE_MIN 0x0500
#define PULSE_MAX 0x0D00
#define PULSE_TIMEOUT 0x0F00
#define PULSE_CENTER 0x08C0
/* moving average filters */
#define PULSE_FILTER_FAST (1<<2)
#define PULSE_FILTER_SLOW (1<<4)
#define PULSE_FILTER_DIFF 16 /* point to switch filters */
#define PULSE_MID_DIFF 50 /* minimum diff to center */
#define VALUE_RANGE 256
#define ROUND_DIV256(x) ((x >> 8) + ((x & 0x80) ? 1 : 0))
static uint32_t ppm_arr[MAX_CHANNELS];
static uint32_t ch, cnt, valid;
struct channel_data {
uint16_t width;
uint16_t width_slow;
uint16_t filter; /* 0 - fast filter, 1 - slow filter */
uint16_t min; /* minimum value during calibration */
uint16_t mid; /* center value */
uint16_t max; /* maximum value */
};
static struct channel_data ch_data[MAX_CHANNELS];
static uint32_t index, count, valid, cal_in_progress;
static void ppm_isr(void)
{
/* RC Compare -> no TIOA1 edge for 2.5ms */
uint32_t status = *AT91C_TC1_SR;
if (status & AT91C_TC_CPCS) {
if (status & AT91C_TC_CPCS) {
/* average channel count */
cnt = ((cnt * 7) + (ch << 8)) / 8;
count = ((count * 7) + (index << 8)) / 8;
/* at least 4 channels and a stable channel count */
valid = (ROUND_DIV256(cnt) == ch) && (ch >= 4);
if ((ROUND_DIV256(count) == index) && (index >= 4)) {
if (valid < 10)
valid++;
} else if (valid > 0) {
valid--;
}
/* reset index */
ch = 0;
index = 0;
}
/* edge on TIOA1 */
if (status & AT91C_TC_LDRAS) {
/* get impulse width */
uint16_t ra = *AT91C_TC1_RA;
uint16_t width = *AT91C_TC1_RA;
/* valid range: 1 - 2ms */
if (ra > 0x0500 && ra < 0x0D00) {
if (ch < ARRAY_SIZE(ppm_arr))
ppm_arr[ch] = ((ppm_arr[ch] * 3) + ra) / 4;
if (width > PULSE_MIN && width < PULSE_MAX) {
if (index < ARRAY_SIZE(ch_data)) {
/* calc both filters */
ch_data[index].width = ((ch_data[index].width * (PULSE_FILTER_FAST -1)) + width) / PULSE_FILTER_FAST;
ch_data[index].width_slow = ((ch_data[index].width_slow * (PULSE_FILTER_SLOW -1)) + width) / PULSE_FILTER_SLOW;
ch++;
if (cal_in_progress) {
/* use slow filter values, calc center */
ch_data[index].min = MIN(ch_data[index].width_slow, ch_data[index].min);
ch_data[index].max = MAX(ch_data[index].width_slow, ch_data[index].max);
ch_data[index].mid = (ch_data[index].min + ch_data[index].max) / 2;
}
}
index++;
}
}
}
uint32_t rcontrol_getvalues(struct rc_values *rc)
{
if (valid < 5)
return 0;
uint32_t i;
uint32_t cnt = MIN(ROUND_DIV256(count), ARRAY_SIZE(ch_data));
for (i = 0; i < cnt; i++) {
/* switch between fast and slow filter */
uint16_t filter = (abs(ch_data[i].width - ch_data[i].width_slow) < PULSE_FILTER_DIFF);
/*
struct cal_data {
uint16_t min;
uint16_t mid;
uint16_t max;
};
int16_t getval(struct cal_data *cal, uint16_t input)
{
int32_t x = (input - cal->mid) * 1024;
uint32_t y = (x > 0) ? (cal->max - cal->mid) : (cal->mid - cal->min);
return x / y;
}
* transition fast -> slow filter
* slow filter is lagging behind, so give it a boost
*/
if (filter && !ch_data[i].filter && !cal_in_progress)
ch_data[i].width_slow = ch_data[i].width;
uint32_t rc_ppm_getvalues(struct rc_values *rc)
ch_data[i].filter = filter;
uint16_t width = (filter) ? ch_data[i].width_slow : ch_data[i].width;
/* expand the value to +/- VALUE_RANGE */
int32_t tmp = (width - ch_data[i].mid) * VALUE_RANGE;
tmp = tmp / ((tmp > 0) ? (ch_data[i].max - ch_data[i].mid) : (ch_data[i].mid - ch_data[i].min));
/* keep result in range */
if (tmp > VALUE_RANGE)
tmp = VALUE_RANGE;
if (tmp < -VALUE_RANGE)
tmp = -VALUE_RANGE;
rc->chan[i] = tmp;
}
return cnt;
}
void rcontrol_calibrate(uint32_t mode)
{
uint32_t i;
rc->count = MIN(ROUND_DIV256(cnt), ARRAY_SIZE(ppm_arr));
for (i = 0; i < rc->count; i++)
rc->ch[i] = (ppm_arr[i] - 0x8C0);
return valid;
switch (mode) {
case RC_CAL_START:
cal_in_progress = 1;
for (i = 0; i < ARRAY_SIZE(ch_data); i++) {
/* use hard limits as hint */
ch_data[i].max = PULSE_MIN;
ch_data[i].mid = (PULSE_MIN + PULSE_MAX) / 2;
ch_data[i].min = PULSE_MAX;
}
break;
case RC_CAL_END:
cal_in_progress = 0;
for (i = 0; i < ARRAY_SIZE(ch_data); i++) {
/* treat current position as center */
ch_data[i].mid = ch_data[i].width_slow;
/* if center is near minimum, clamp output to 0..+1024 */
if (ch_data[i].mid - ch_data[i].min < PULSE_MID_DIFF)
ch_data[i].mid = ch_data[i].min;
/* if center is near maximum, clamp output to -1024..0 */
if (ch_data[i].max - ch_data[i].mid < PULSE_MID_DIFF)
ch_data[i].mid = ch_data[i].max;
}
break;
}
}
void rcontrol_print_cal(void)
{
uint32_t i;
for (i = 0; i < ARRAY_SIZE(ch_data); i++) {
printf("%ld: %d(%+d) - %d(0) - %d(%+d)\n\r", i,
ch_data[i].min, ch_data[i].min - ch_data[i].mid,
ch_data[i].mid,
ch_data[i].max, ch_data[i].max - ch_data[i].mid
);
}
}
void at91_tc1_init(void)
@ -97,7 +194,7 @@ void at91_tc1_init(void)
*AT91C_TC1_IER = AT91C_TC_LDRAS | AT91C_TC_CPCS;
/* RC Compare Interrupt if no rising Edge on TIOA1 for 2.56ms */
*AT91C_TC1_RC = 0x0F00;
*AT91C_TC1_RC = PULSE_TIMEOUT;
/* enable & trigger the clock */
*AT91C_TC1_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
@ -108,3 +205,21 @@ void at91_tc1_init(void)
aic->AIC_SVR[AT91C_ID_TC1] = (uint32_t)ppm_isr;
aic->AIC_IECR = (1 << AT91C_ID_TC1);
}
static void tast_monitor(uint32_t status, uint32_t input)
{
if (!(input & TAST1) && (cal_in_progress == 0)) {
printf("start calibration\n\r");
rcontrol_calibrate(RC_CAL_START);
} else if (!(input & TAST2) && (cal_in_progress == 1)) {
printf("end calibration\n\r");
rcontrol_calibrate(RC_CAL_END);
rcontrol_print_cal();
}
}
PIO_PINCHANGE_ISR(TAST1 | TAST2, tast_monitor);

2
src/at91_udp.c
View File

@ -428,8 +428,6 @@ static void udp_isr(void)
uint32_t isr = *AT91C_UDP_ISR;
if (isr & AT91C_UDP_ENDBUSRES) {
printf("usb reset\n\r");
AT91S_UDP *udp = AT91C_BASE_UDP;
/* reset all endpoints */