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/**
* <rc/encoder.h>
*
* @brief C interface for quadrature encoder counting.
*
* Functions for reading the eQEP hardware-accelerated quadrature encoder
* counters and the PRU accelerated encoder counter.Channels 1-3 on the Robotics
* Cape and BeagleBone Blue are counted using the Sitara's eQEP counter. Channel
* 4 is counted with the PRU.
*
*
* @author James Strawson
* @date 5/12/2018
*
* @addtogroup Encoder
* @ingroup Quadrature_Encoder
* @{
*/
#ifndef RC_ENCODER_H
#define RC_ENCODER_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Initializes counters for channels 1-4
*
* This also resets the encoder position to 0 so the first position read is
* consistent.
*
* @return 0 on success or -1 on failure
*/
int rc_encoder_init(void);
/**
* @brief Stops the encoder counters and closes file descriptors. This is
* not strictly necessary but is recommended that the user calls this function
* at the end of their program.
*
* @return 0 on success or -1 on failure.
*/
int rc_encoder_cleanup(void);
/**
* @brief Reads the current position of an encoder channel.
*
* This is a signed 32-bit integer that wraps around if the position is allowed
* to read +- 2^31
*
* @param[in] ch channel 1-4
*
* @return The current position (signed 32-bit integer) or -1 and prints an
* error message is there is a problem.
*/
int rc_encoder_read(int ch);
/**
* @brief Sets the current position of an eQEP encoder channel. Usually for
* resetting a counter to 0 but can set an arbitrary position if desired.
*
* @param[in] ch channel 1-4
* @param[in] pos The new position
*
* @return 0 on success, -1 on failure
*/
int rc_encoder_write(int ch, int pos);
#ifdef __cplusplus
}
#endif
#endif // RC_ENCODER_H
/** @} end group Encoder*/