This is the description of the C/C++ for Microcontrollers API bindings for the Motorized Linear Poti Bricklet. General information and technical specifications for the Motorized Linear Poti Bricklet are summarized in its hardware description.
An installation guide for the C/C++ for Microcontrollers API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | // This example is not self-contained.
// It requires usage of the example driver specific to your platform.
// See the HAL documentation.
#include "src/bindings/hal_common.h"
#include "src/bindings/bricklet_motorized_linear_poti.h"
void check(int rc, const char *msg);
void example_setup(TF_HAL *hal);
void example_loop(TF_HAL *hal);
static TF_MotorizedLinearPoti mlp;
void example_setup(TF_HAL *hal) {
// Create device object
check(tf_motorized_linear_poti_create(&mlp, NULL, hal), "create device object");
// Get current position
uint16_t position;
check(tf_motorized_linear_poti_get_position(&mlp, &position), "get position");
tf_hal_printf("Position: %I16u\n", position); // Range: 0 to 100
}
void example_loop(TF_HAL *hal) {
// Poll for callbacks
tf_hal_callback_tick(hal, 0);
}
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | // This example is not self-contained.
// It requires usage of the example driver specific to your platform.
// See the HAL documentation.
#include "src/bindings/hal_common.h"
#include "src/bindings/bricklet_motorized_linear_poti.h"
void check(int rc, const char *msg);
void example_setup(TF_HAL *hal);
void example_loop(TF_HAL *hal);
// Callback function for position callback
static void position_handler(TF_MotorizedLinearPoti *device, uint16_t position,
void *user_data) {
(void)device; (void)user_data; // avoid unused parameter warning
tf_hal_printf("Position: %I16u\n", position); // Range: 0 to 100
}
static TF_MotorizedLinearPoti mlp;
void example_setup(TF_HAL *hal) {
// Create device object
check(tf_motorized_linear_poti_create(&mlp, NULL, hal), "create device object");
// Register position callback to function position_handler
tf_motorized_linear_poti_register_position_callback(&mlp,
position_handler,
NULL);
// Set period for position callback to 0.05s (50ms) without a threshold
tf_motorized_linear_poti_set_position_callback_configuration(&mlp, 50, false, 'x', 0, 0);
}
void example_loop(TF_HAL *hal) {
// Poll for callbacks
tf_hal_callback_tick(hal, 0);
}
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | // This example is not self-contained.
// It requires usage of the example driver specific to your platform.
// See the HAL documentation.
#include "src/bindings/hal_common.h"
#include "src/bindings/bricklet_motorized_linear_poti.h"
void check(int rc, const char *msg);
void example_setup(TF_HAL *hal);
void example_loop(TF_HAL *hal);
// Callback function for position reached callback
static void position_reached_handler(TF_MotorizedLinearPoti *device, uint16_t position,
void *user_data) {
(void)device; (void)user_data; // avoid unused parameter warning
tf_hal_printf("Position: %I16u\n", position); // Range: 0 to 100
}
static TF_MotorizedLinearPoti mlp;
void example_setup(TF_HAL *hal) {
// Create device object
check(tf_motorized_linear_poti_create(&mlp, NULL, hal), "create device object");
// Register position reached callback to function position_reached_handler
tf_motorized_linear_poti_register_position_reached_callback(&mlp,
position_reached_handler,
NULL);
// Move slider smooth to the middle
check(tf_motorized_linear_poti_set_motor_position(&mlp, 50,
TF_MOTORIZED_LINEAR_POTI_DRIVE_MODE_SMOOTH,
false), "call set_motor_position");
}
void example_loop(TF_HAL *hal) {
// Poll for callbacks
tf_hal_callback_tick(hal, 0);
}
|
Most functions of the C/C++ bindings for microcontrollers return an error code
(e_code
).
Possible error codes are:
(as defined in errors.h
) as well as the errors returned from
the hardware abstraction layer (HAL) that is used.
Use :cpp:func`tf_hal_strerror` (defined in the HAL's header file) to get an error string for an error code.
Data returned from the device, when a getter is called,
is handled via output parameters. These parameters are labeled with the
ret_
prefix. The bindings will not write to an output parameter if NULL or nullptr
is passed. This can be used to ignore outputs that you are not interested in.
None of the functions listed below are thread-safe. See the API bindings description for details.
tf_motorized_linear_poti_create
(TF_MotorizedLinearPoti *motorized_linear_poti, const char *uid_or_port_name, TF_HAL *hal)¶Parameters: |
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---|---|
Returns: |
|
Creates the device object motorized_linear_poti
with the optional unique device ID or port name
uid_or_port_name
and adds it to the HAL hal
:
TF_MotorizedLinearPoti motorized_linear_poti;
tf_motorized_linear_poti_create(&motorized_linear_poti, NULL, &hal);
Normally uid_or_port_name
can stay NULL
. For more details about this
see section UID or Port Name.
tf_motorized_linear_poti_destroy
(TF_MotorizedLinearPoti *motorized_linear_poti)¶Parameters: |
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Returns: |
|
Removes the device object motorized_linear_poti
from its HAL and destroys it.
The device object cannot be used anymore afterwards.
tf_motorized_linear_poti_get_position
(TF_MotorizedLinearPoti *motorized_linear_poti, uint16_t *ret_position)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the position of the linear potentiometer. The value is between 0 (slider down) and 100 (slider up).
If you want to get the value periodically, it is recommended to use the
Position
callback. You can set the callback configuration
with tf_motorized_linear_poti_set_position_callback_configuration()
.
tf_motorized_linear_poti_set_motor_position
(TF_MotorizedLinearPoti *motorized_linear_poti, uint16_t position, uint8_t drive_mode, bool hold_position)¶Parameters: |
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---|---|
Returns: |
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Sets the position of the potentiometer. The motorized potentiometer will immediately start to approach the position. Depending on the chosen drive mode, the position will either be reached as fast as possible or in a slow but smooth motion.
The position has to be between 0 (slider down) and 100 (slider up).
If you set the hold position parameter to true, the position will automatically be retained. If a user changes the position of the potentiometer, it will automatically drive back to the original set point.
If the hold position parameter is set to false, the potentiometer can be changed again by the user as soon as the set point was reached once.
The following constants are available for this function:
For drive_mode:
tf_motorized_linear_poti_get_motor_position
(TF_MotorizedLinearPoti *motorized_linear_poti, uint16_t *ret_position, uint8_t *ret_drive_mode, bool *ret_hold_position, bool *ret_position_reached)¶Parameters: |
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---|---|
Output Parameters: |
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Returns: |
|
Returns the last motor position as set by tf_motorized_linear_poti_set_motor_position()
. This is not
the current position (use tf_motorized_linear_poti_get_position()
to get the current position). This
is the last used set point and configuration.
The position reached parameter is true if the position has been reached at one point. The position may have been changed again in the meantime by the user.
The following constants are available for this function:
For ret_drive_mode:
tf_motorized_linear_poti_calibrate
(TF_MotorizedLinearPoti *motorized_linear_poti)¶Parameters: |
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Returns: |
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Starts a calibration procedure. The potentiometer will be driven to the extreme points to calibrate the potentiometer.
The calibration is saved in flash, it does not have to be called on every start up.
The Motorized Linear Poti Bricklet is already factory-calibrated during testing at Tinkerforge.
tf_motorized_linear_poti_get_spitfp_error_count
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t *ret_error_count_ack_checksum, uint32_t *ret_error_count_message_checksum, uint32_t *ret_error_count_frame, uint32_t *ret_error_count_overflow)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
tf_motorized_linear_poti_set_status_led_config
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t config)¶Parameters: |
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Returns: |
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Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.
The following constants are available for this function:
For config:
tf_motorized_linear_poti_get_status_led_config
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t *ret_config)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the configuration as set by tf_motorized_linear_poti_set_status_led_config()
The following constants are available for this function:
For ret_config:
tf_motorized_linear_poti_get_chip_temperature
(TF_MotorizedLinearPoti *motorized_linear_poti, int16_t *ret_temperature)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!
The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.
tf_motorized_linear_poti_reset
(TF_MotorizedLinearPoti *motorized_linear_poti)¶Parameters: |
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---|---|
Returns: |
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Calling this function will reset the Bricklet. All configurations will be lost.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
tf_motorized_linear_poti_get_identity
(TF_MotorizedLinearPoti *motorized_linear_poti, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
tf_motorized_linear_poti_set_position_callback_configuration
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t period, bool value_has_to_change, char option, uint16_t min, uint16_t max)¶Parameters: |
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Returns: |
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The period is the period with which the Position
callback is triggered
periodically. A value of 0 turns the callback off.
If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.
If it is set to false, the callback is continuously triggered with the period, independent of the value.
It is furthermore possible to constrain the callback with thresholds.
The option-parameter together with min/max sets a threshold for the Position
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.
The following constants are available for this function:
For option:
tf_motorized_linear_poti_get_position_callback_configuration
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t *ret_period, bool *ret_value_has_to_change, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the callback configuration as set by tf_motorized_linear_poti_set_position_callback_configuration()
.
The following constants are available for this function:
For ret_option:
tf_motorized_linear_poti_set_position_reached_callback_configuration
(TF_MotorizedLinearPoti *motorized_linear_poti, bool enabled)¶Parameters: |
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Returns: |
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Enables/Disables Position Reached
callback.
tf_motorized_linear_poti_get_position_reached_callback_configuration
(TF_MotorizedLinearPoti *motorized_linear_poti, bool *ret_enabled)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the Position Reached
callback configuration
as set by tf_motorized_linear_poti_set_position_reached_callback_configuration()
.
Callbacks can be registered to receive time critical or recurring data from the
device. The registration is done with the corresponding tf_motorized_linear_poti_register_*_callback
function.
The user_data
passed to the registration function as well as the device that triggered the callback are
passed to the registered callback handler.
Only one handler can be registered to a callback at the same time.
To deregister a callback, call the tf_motorized_linear_poti_register_*_callback
function
with NULL as handler.
Note
Using callbacks for recurring events is preferred compared to using getters. Polling for a callback requires writing one byte only. See here Optimizing Performance.
Warning
Calling bindings function from inside a callback handler is not allowed. See here Thread safety.
tf_motorized_linear_poti_register_position_callback
(TF_MotorizedLinearPoti *motorized_linear_poti, TF_MotorizedLinearPoti_PositionHandler handler, void *user_data)¶void handler(TF_MotorizedLinearPoti *motorized_linear_poti, uint16_t position, void *user_data)
Callback Parameters: |
|
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This callback is triggered periodically according to the configuration set by
tf_motorized_linear_poti_set_position_callback_configuration()
.
The parameter is the same as tf_motorized_linear_poti_get_position()
.
tf_motorized_linear_poti_register_position_reached_callback
(TF_MotorizedLinearPoti *motorized_linear_poti, TF_MotorizedLinearPoti_PositionReachedHandler handler, void *user_data)¶void handler(TF_MotorizedLinearPoti *motorized_linear_poti, uint16_t position, void *user_data)
Callback Parameters: |
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This callback is triggered if a new position as set by
tf_motorized_linear_poti_set_motor_position()
is reached.
The parameter is the current position.
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object.
tf_motorized_linear_poti_get_response_expected
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t function_id, bool *ret_response_expected)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.
For getter functions this is enabled by default and cannot be disabled,
because those functions will always send a response. For callback configuration
functions it is enabled by default too, but can be disabled by
tf_motorized_linear_poti_set_response_expected()
. For setter functions it is disabled by default
and can be enabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For function_id:
tf_motorized_linear_poti_set_response_expected
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t function_id, bool response_expected)¶Parameters: |
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Returns: |
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Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For function_id:
tf_motorized_linear_poti_set_response_expected_all
(TF_MotorizedLinearPoti *motorized_linear_poti, bool response_expected)¶Parameters: |
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Returns: |
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Changes the response expected flag for all setter and callback configuration functions of this device at once.
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
tf_motorized_linear_poti_set_bootloader_mode
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t mode, uint8_t *ret_status)¶Parameters: |
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Output Parameters: |
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Returns: |
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Sets the bootloader mode and returns the status after the requested mode change was instigated.
You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
The following constants are available for this function:
For mode:
For ret_status:
tf_motorized_linear_poti_get_bootloader_mode
(TF_MotorizedLinearPoti *motorized_linear_poti, uint8_t *ret_mode)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the current bootloader mode, see tf_motorized_linear_poti_set_bootloader_mode()
.
The following constants are available for this function:
For ret_mode:
tf_motorized_linear_poti_set_write_firmware_pointer
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t pointer)¶Parameters: |
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Returns: |
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Sets the firmware pointer for tf_motorized_linear_poti_write_firmware()
. The pointer has
to be increased by chunks of size 64. The data is written to flash
every 4 chunks (which equals to one page of size 256).
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
tf_motorized_linear_poti_write_firmware
(TF_MotorizedLinearPoti *motorized_linear_poti, const uint8_t data[64], uint8_t *ret_status)¶Parameters: |
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Output Parameters: |
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Returns: |
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Writes 64 Bytes of firmware at the position as written by
tf_motorized_linear_poti_set_write_firmware_pointer()
before. The firmware is written
to flash every 4 chunks.
You can only write firmware in bootloader mode.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
tf_motorized_linear_poti_write_uid
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t uid)¶Parameters: |
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Returns: |
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Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.
We recommend that you use Brick Viewer to change the UID.
tf_motorized_linear_poti_read_uid
(TF_MotorizedLinearPoti *motorized_linear_poti, uint32_t *ret_uid)¶Parameters: |
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Output Parameters: |
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Returns: |
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Returns the current UID as an integer. Encode as Base58 to get the usual string version.
TF_MOTORIZED_LINEAR_POTI_DEVICE_IDENTIFIER
¶This constant is used to identify a Motorized Linear Poti Bricklet.
The functions tf_motorized_linear_poti_get_identity()
and tf_hal_get_device_info()
have a device_identifier
output parameter to specify
the Brick's or Bricklet's type.
TF_MOTORIZED_LINEAR_POTI_DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Motorized Linear Poti Bricklet.