// send cnt bits to LCD controller, only low bits of "bits" are used
// use timer4 to get 600kHz clock for driving WR/ signal
// timer is used in one-pulse mode and is started after each WR/ change,
// so there will always be minimal required length of pulse also
// when interrupted by some interrupt
static void lcd_send_bits(u8 cnt, u16 bits) {
// shift bits to high-bits
bits <<= (u8)(16 - cnt);
WR0;
BSET(TIM4_CR1, 0); // start timer
WR0; // optimize hack
do {
if (bits & 0x8000) {
DATA1;
}
else {
DATA0;
}
bits <<= 1; // to next bit
while (!BCHK(TIM4_SR, 0)); // wait for timer
WR1;
BRES(TIM4_SR, 0); // clear intr flag
BSET(TIM4_CR1, 0); // start timer
if (!--cnt) break;
while (!BCHK(TIM4_SR, 0)); // wait for timer
WR0;
BRES(TIM4_SR, 0); // clear intr flag
BSET(TIM4_CR1, 0); // start timer
} while (1);
while (!BCHK(TIM4_SR, 0)); // wait for timer
BRES(TIM4_SR, 0); // clear intr flag
}
/*
TIM3 overflow interrupt
set next prescaler, output compare and overflow values to
preload registers
*/
@interrupt void ppm_interrupt(void) {
BRES(TIM3_SR1, 0); // erase interrupt flag
if (ppm_channel2) {
if (ppm_channel2 == 2) {
// will be setting channel1 servo, so we are now generating
// SYNC signal in HW
// wakeup CALC task to compute new PPM values
// values for ARR registers will be updated after calculate done
// (and when we are still generating SYNC pulse)
awake(CALC);
}
// set servo channel
TIM3_PSCR = PPM_PSC_SERVO;
TIM3_CCR2H = hi8(PPM_300US_SERVO);
TIM3_CCR2L = lo8(PPM_300US_SERVO);
TIM3_ARRH = ppm_values[ppm_channel2];
ppm_channel2++;
TIM3_ARRL = ppm_values[ppm_channel2];
if (++ppm_channel2 > channels2) {
// next to SYNC pulse
ppm_channel2 = 0;
}
return;
}
// set SYNC signal
TIM3_PSCR = PPM_PSC_SYNC;
TIM3_CCR2H = hi8(PPM_300US_SYNC);
TIM3_CCR2L = lo8(PPM_300US_SYNC);
TIM3_ARRH = ppm_values[0];
TIM3_ARRL = ppm_values[1];
ppm_channel2 = 2; // to first channel (step 2 bytes)
}
static void read_ADC(void) {
u16 *buf = adc_buffer[adc_buffer_pos];
u8 dead;
ADC_NEWVAL(0);
ADC_NEWVAL(1);
ADC_NEWVAL(2);
adc_battery_last = ADC_DB3R;
adc_buffer_pos++;
adc_buffer_pos &= 3;
BRES(ADC_CSR, 7); // remove EOC flag
BSET(ADC_CR1, 0); // start new conversion
// average battery voltage and check battery low
// ignore very low, which means that it is supplied from SWIM connector
adc_battery_filt = adc_battery_filt * (ADC_BAT_FILT - 1); // splitted - compiler hack
adc_battery_filt = (adc_battery_filt + (ADC_BAT_FILT / 2)) / ADC_BAT_FILT
+ adc_battery_last;
adc_battery = (u16)((adc_battery_filt + (ADC_BAT_FILT / 2)) / ADC_BAT_FILT);
// start checking battery after 5s from power on
if (time_sec >= 5) {
// wakeup task only when something changed
if (adc_battery > 50 && adc_battery < battery_low_raw) {
// bat low
if (!menu_battery_low) {
menu_battery_low = 1;
awake(MENU);
}
}
else {
// bat OK, but apply some hysteresis to not switch quickly ON/OFF
if (menu_battery_low && adc_battery > battery_low_raw + 100) {
menu_battery_low = 0;
awake(MENU);
}
}
}
// wakeup MENU task when showing battery or at calibrate
if (menu_wants_adc)
awake(MENU);
// reset inactivity timer when some steering or throttle applied
dead = cg.steering_dead_zone;
if (dead < 20) dead = 20; // use some minimal dead zone for this check
if (adc_steering_last < (cg.calib_steering_mid - dead) ||
adc_steering_last > (cg.calib_steering_mid + dead))
reset_inactivity_timer();
else {
dead = cg.throttle_dead_zone;
if (dead < 20) dead = 20; // use some minimal dead zone for this check
if (adc_throttle_last < (cg.calib_throttle_mid - dead) ||
adc_throttle_last > (cg.calib_throttle_mid + dead))
reset_inactivity_timer();
}
}
// set number of channels
void ppm_set_channels(u8 n) {
// disable PPM generation till new values will not be set
ppm_enabled = 0;
BRES(TIM3_CR1, 0); // disable timer
BSET(PD_ODR, 0); // set PPM pin to 1
// start with generating 20ms SYNC signal
TIM3_CCR2H = hi8(PPM_300US_SYNC);
TIM3_CCR2L = hi8(PPM_300US_SYNC);
TIM3_ARRH = hi8(PPM_MUL_SYNC * 20);
TIM3_ARRL = lo8(PPM_MUL_SYNC * 20);
channels = n;
channels2 = (u8)(n << 1); // also 2* value for compare in ppm_interrupt
}
