servos_ppm_hw.h File Reference

Efficient driving of MAT0.1 (SERVO_CLOCK_PIN) using TIMER0 to produce PPM for a R/C receiver which has a microcontroller to drive the servos (not a 4015 or 4017 decade counter chip). More...

#include "std.h"
#include "LPC21xx.h"
#include "mcu_periph/sys_time.h"
#include <BOARD_CONFIG>

Include dependency graph for servos_ppm_hw.h:

Go to the source code of this file.

Macros
#define	SERVOS_TICS_OF_USEC(s)   cpu_ticks_of_usec(s)
#define	ChopServo(x, a, b)   Chop(x, a, b)
#define	_PPM_NB_CHANNELS   8
#define	ActuatorPpmSet(_i, _v)   { servos_values[_i] = SERVOS_TICS_OF_USEC(_v); }
#define	ActuatorsPpmCommit()   {}
#define	ActuatorsPpmInit()   actuators_ppm_init()
#define	SERVO_REFRESH_TICS   SERVOS_TICS_OF_USEC(22000)
#define	PPM_WIDTH   SERVOS_TICS_OF_USEC(550)
#define	ACTUATORS_IT   TIR_MR1I
#define	ServosPPMMat_ISR()

Functions
void	actuators_ppm_init (void)

Variables
uint16_t	servos_values [_PPM_NB_CHANNELS]
uint8_t	servos_PPM_idx
uint32_t	servos_delay
uint8_t	ppm_pulse

Detailed Description

Efficient driving of MAT0.1 (SERVO_CLOCK_PIN) using TIMER0 to produce PPM for a R/C receiver which has a microcontroller to drive the servos (not a 4015 or 4017 decade counter chip).

Definition in file servos_ppm_hw.h.

Macro Definition Documentation

#define _PPM_NB_CHANNELS   8

Definition at line 43 of file servos_ppm_hw.h.

Referenced by actuators_ppm_init().

#define ActuatorPpmSet	(		_i,
			_v
	)		{ servos_values[_i] = SERVOS_TICS_OF_USEC(_v); }

Definition at line 45 of file servos_ppm_hw.h.

#define ACTUATORS_IT   TIR_MR1I

Definition at line 59 of file servos_ppm_hw.h.

#define ActuatorsPpmCommit

(

)

{}

Definition at line 48 of file servos_ppm_hw.h.

#define ActuatorsPpmInit

(

)

actuators_ppm_init()

Definition at line 49 of file servos_ppm_hw.h.

#define ChopServo	(		x,
			a,
			b
	)		Chop(x, a, b)

Definition at line 41 of file servos_ppm_hw.h.

#define PPM_WIDTH   SERVOS_TICS_OF_USEC(550)

Definition at line 57 of file servos_ppm_hw.h.

#define SERVO_REFRESH_TICS   SERVOS_TICS_OF_USEC(22000)

Definition at line 55 of file servos_ppm_hw.h.

#define SERVOS_TICS_OF_USEC

(

s

)

cpu_ticks_of_usec(s)

Definition at line 40 of file servos_ppm_hw.h.

#define ServosPPMMat_ISR

(

)

Value:

{                                        \
    if (servos_PPM_idx == 0) {                                      \
      servos_delay = SERVO_REFRESH_TICS;                            \
    }                                                               \
    if (servos_PPM_idx < _PPM_NB_CHANNELS ) {                       \
      if (ppm_pulse) {                                              \
        T0MR1 += PPM_WIDTH;                                         \
        servos_delay -= PPM_WIDTH;                                  \
      } else {                                                      \
        T0MR1 += servos_values[servos_PPM_idx] - PPM_WIDTH;         \
        servos_delay -= servos_values[servos_PPM_idx] - PPM_WIDTH;  \
        servos_PPM_idx++;                                           \
      }                                                             \
    } else { /* servos_PPM_idx=_PPM_NB_CHANNELS */                  \
      if (ppm_pulse) {                                              \
        T0MR1 += PPM_WIDTH;                                         \
        servos_delay -= PPM_WIDTH;                                  \
      } else {                                                      \
        servos_PPM_idx = 0;                                         \
        T0MR1 += servos_delay - PPM_WIDTH;                          \
      }                                                             \
    }                                                               \
    if (!ppm_pulse) {                                               \
      /* lower clock pin */                                         \
      T0EMR &= ~TEMR_EM1;                                           \
    }                                                               \
    /* toggle ppm_pulse flag */                                     \
    ppm_pulse ^= 1;                                                 \
  }

Definition at line 60 of file servos_ppm_hw.h.

Referenced by TIMER0_ISR().

Function Documentation

void actuators_ppm_init

(

void

)

Definition at line 41 of file servos_ppm_hw.c.

References _PPM_NB_CHANNELS, SERVO_CLOCK_PINSEL, SERVO_CLOCK_PINSEL_BIT, SERVO_CLOCK_PINSEL_VAL, SERVO_REFRESH_TICS, servos_delay, servos_PPM_idx, SERVOS_TICS_OF_USEC, servos_values, START_TIMEOUT, T0EMR, T0MCR, T0MR1, TEMR_EM1, TEMR_EMC1_2, and TMCR_MR1_I.

Variable Documentation

uint8_t ppm_pulse

Definition at line 36 of file servos_ppm_hw.c.

uint32_t servos_delay

Definition at line 33 of file servos_4015_MAT_hw.c.

Referenced by actuators_4015_init(), and actuators_ppm_init().

uint8_t servos_PPM_idx

Definition at line 35 of file servos_ppm_hw.c.

Referenced by actuators_ppm_init().

uint16_t servos_values[_PPM_NB_CHANNELS]

Definition at line 29 of file servos_4015_hw.c.

Referenced by actuators_4015_init(), actuators_4017_init(), actuators_ppm_init(), and PWM_ISR().