gwa_encoder.h File Reference

Encoder function prototypes. More...

#include <stdint.h>

Macros
#define	MAX_ENCODER_CHANNEL   4
#define	ENCODER_CHANNEL_BASE0   0
	First encoder on the BASE board (TIM4 PD12-PD13)
#define	ENCODER_CHANNEL_BASE1   1
	Second encoder on the BASE board (TIM3 PB4-PC7)
#define	ENCODER_CHANNEL_EXP0   2
	Encoder on the EXPANSION board (TIM2 PA15-PB3)
#define	ENCODER_CHANNEL_EXP1   3
	Encoder EXPANSION (TIM1 PA8-PE11)
#define	ENCODER_DIR_UP   0
	Counting direction up.
#define	ENCODER_DIR_DOWN   1
	Counting direction down.
#define	ENC_OK   0
	No errors.
#define	ENC_INVALID_PARAM   1
	Invalid parameter error.

Functions
int	gwa_encoder_init (uint8_t channel, uint8_t direction, uint32_t value)
	Sets up the encoder.
int	gwa_encoder_read (uint8_t channel, uint32_t *value)
	Reads the value of the counter.
int	gwa_encoder_enable_ovr_int (uint8_t channel)
	Enables the overflow interrupt.
int	gwa_encoder_disable_ovr_int (uint8_t channel)
	Disables the overflow interrupt.
int	gwa_encoder_clear_ovr_int (uint8_t channel)
	Acknowledges the overflow interrupt.
int	gwa_encoder_handle_ovr_int (uint8_t channel)
	Handles overflow interrupt so that encoder value is 32-bit wide.

Detailed Description

Encoder function prototypes.

Author

Tecnologix, 2017

Function Documentation

gwa_encoder_clear_ovr_int()

int gwa_encoder_clear_ovr_int

(

uint8_t

channel

)

Acknowledges the overflow interrupt.

Parameters

channel

encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1

Returns

ENC_OK if everything is ok, an error code otherwise.

gwa_encoder_disable_ovr_int()

int gwa_encoder_disable_ovr_int

(

uint8_t

channel

)

Disables the overflow interrupt.

Parameters

channel

encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1

Returns

ENC_OK if everything is ok, an error code otherwise.

gwa_encoder_enable_ovr_int()

int gwa_encoder_enable_ovr_int

(

uint8_t

channel

)

Enables the overflow interrupt.

Parameters

channel

encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1

Returns

ENC_OK if everything is ok, an error code otherwise.

gwa_encoder_handle_ovr_int()

int gwa_encoder_handle_ovr_int

(

uint8_t

channel

)

Handles overflow interrupt so that encoder value is 32-bit wide.

This function must be called from the timer IRQ handler of the peripheral used for the encoder:

• ENCODER_CHANNEL_BASE0 -> TIM4
• ENCODER_CHANNEL_BASE1 -> TIM3
• ENCODER_CHANNEL_EXP0 -> TIM2
• ENCODER_CHANNEL_EXP1 -> TIM1

This function checks if the overflow interrupt flag is set and clears it so it can be called from the timer IRQ handler without any check on the interrupt type.

Parameters

channel

encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1

Returns

ENC_OK if everything is ok, an error code otherwise.

gwa_encoder_init()

int gwa_encoder_init	(	uint8_t	channel,
		uint8_t	direction,
		uint32_t	value )

Sets up the encoder.

Parameters

channel	encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1
direction	specifies if the counter counts up (ENCODER_DIR_UP) or down (ENCODER_DIR_DOWN).
value	initial value of the counter.

Returns

ENC_OK if everything is ok, an error code otherwise.

gwa_encoder_read()

int gwa_encoder_read	(	uint8_t	channel,
		uint32_t *	value )

Reads the value of the counter.

Parameters

channel	encoder channel: ENCODER_CHANNEL_BASE0 ENCODER_CHANNEL_BASE1 ENCODER_CHANNEL_EXP0 ENCODER_CHANNEL_EXP1
value	pointer to a variable that holds the counter value

Returns

ENC_OK if everything is ok, an error code otherwise.