From: Jan "Yenya" Kasprzak Date: Fri, 7 Dec 2012 21:03:49 +0000 (+0100) Subject: pwmled.c: save error sum between mode switches X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=commitdiff_plain;h=b075b225aa743ebb6ce09ca2d1be42e81a6c9ad8;p=bike-lights.git pwmled.c: save error sum between mode switches otherwise it leads to instability when during short blink the error sum does not manage to increase the stride. Also, use 32-bit ints to simplify the code and save some branches. --- diff --git a/firmware/pwmled.c b/firmware/pwmled.c index 3e4e1f4..d70013e 100644 --- a/firmware/pwmled.c +++ b/firmware/pwmled.c @@ -7,6 +7,7 @@ typedef struct { int16_t err_sum; unsigned char mode, state, probe_steps; uint16_t mode_pwm[N_PWMLED_MODES]; + int16_t err_sums[N_PWMLED_MODES]; } pwmled_t; pwmled_t pwmleds[N_PWMLEDS]; @@ -81,8 +82,10 @@ void init_pwmled() led->state = ST_PROBING; led->probe_steps = 0; - for (j = 0; j < N_PWMLED_MODES; j++) + for (j = 0; j < N_PWMLED_MODES; j++) { led->mode_pwm[j] = 0; + led->err_sums[j] = 0; + } } } @@ -93,11 +96,10 @@ void pwmled_set_mode(unsigned char n, unsigned char mode) if (!ST_CAN_SET_MODE(led->state)) return; - if (led->mode) // save the previous state + if (led->mode) { // save the previous state led->mode_pwm[led->mode - 1] = led->pwm; - - if (n == 1) - log_byte(mode); + led->err_sums[led->mode - 1] = led->err_sum; + } led->mode = mode; @@ -105,7 +107,7 @@ void pwmled_set_mode(unsigned char n, unsigned char mode) led->target = adc_vals[n*N_PWMLED_MODES + mode - 1]; led->state = ST_ON; led->pwm = led->mode_pwm[mode - 1]; - led->err_sum = 0; + led->err_sum = led->err_sums[mode - 1]; pwm_set(n, led->pwm); } else { led->state = ST_OFF; @@ -116,34 +118,28 @@ void pwmled_set_mode(unsigned char n, unsigned char mode) void pwmled_adc(unsigned char n, uint16_t adcval) { pwmled_t *led = pwmleds + n; - int16_t sum, pwm_div; uint16_t old_pwm; + int32_t sum; + unsigned char shift; if (!ST_IS_ON(led->state)) return; // FIXME: test for maximum adcval value (adc_max[n]) - sum = led->err_sum += (int16_t)(led->target) - (int16_t)adcval; - - // FIXME: try to work faster during probing - pwm_div = 64; //led->state == ST_PROBING ? (1 << 5) : (1 << 8); old_pwm = led->pwm; - if (sum >= pwm_div) { - uint16_t diff = sum/pwm_div; - led->pwm += diff; - led->err_sum -= diff * pwm_div; + shift = led->state == ST_PROBING ? 3 : 5; - } else if (sum <= -pwm_div) { - uint16_t diff = (-sum)/pwm_div; + sum = ((int32_t)led->pwm << shift) + + led->err_sum + led->target - adcval; - if (led->pwm >= diff) - led->pwm -= (int16_t)diff; - else - led->pwm = 0; - led->err_sum += diff * pwm_div; - } + if (sum < 0) + sum = 0; + + led->pwm = sum >> shift; + sum -= led->pwm << shift; + led->err_sum = sum; if (led->state == ST_PROBING) { if (led->pwm == old_pwm) {