This is the description of the C/C++ API bindings for the Segment Display 4x7 Bricklet. General information and technical specifications for the Segment Display 4x7 Bricklet are summarized in its hardware description.
An installation guide for the C/C++ 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 29 30 31 32 33 34 35 36 37 38 39 40 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_segment_display_4x7.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Segment Display 4x7 Bricklet
const uint8_t digits[] = {0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71}; // 0~9,A,b,C,d,E,F
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
SegmentDisplay4x7 sd;
segment_display_4x7_create(&sd, UID, &ipcon);
// Connect to brickd
if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
fprintf(stderr, "Could not connect\n");
return 1;
}
// Don't use device before ipcon is connected
// Write "4223" to the display with full brightness without colon
uint8_t segments[4] = {digits[4], digits[2], digits[2], digits[3]};
segment_display_4x7_set_segments(&sd, segments, 7, false);
printf("Press key to exit\n");
getchar();
segment_display_4x7_destroy(&sd);
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
return 0;
}
|
Most functions of the C/C++ bindings return an error code (e_code
).
Data returned from the device, when a getter is called,
is handled via output parameters. These parameters are labeled with the
ret_
prefix.
Possible error codes are:
as defined in ip_connection.h
.
All functions listed below are thread-safe.
segment_display_4x7_create
(SegmentDisplay4x7 *segment_display_4x7, const char *uid, IPConnection *ipcon)¶Parameters: |
|
---|
Creates the device object segment_display_4x7
with the unique device ID uid
and adds
it to the IPConnection ipcon
:
SegmentDisplay4x7 segment_display_4x7;
segment_display_4x7_create(&segment_display_4x7, "YOUR_DEVICE_UID", &ipcon);
This device object can be used after the IP connection has been connected.
segment_display_4x7_destroy
(SegmentDisplay4x7 *segment_display_4x7)¶Parameters: |
|
---|
Removes the device object segment_display_4x7
from its IPConnection and destroys it.
The device object cannot be used anymore afterwards.
segment_display_4x7_set_segments
(SegmentDisplay4x7 *segment_display_4x7, uint8_t segments[4], uint8_t brightness, bool colon)¶Parameters: |
|
---|---|
Returns: |
|
The 7-segment display can be set with bitmaps. Every bit controls one segment:
For example to set a "5" you would want to activate segments 0, 2, 3, 5 and 6. This is represented by the number 0b01101101 = 0x6d = 109.
The brightness can be set between 0 (dark) and 7 (bright). The colon parameter turns the colon of the display on or off.
segment_display_4x7_get_segments
(SegmentDisplay4x7 *segment_display_4x7, uint8_t ret_segments[4], uint8_t *ret_brightness, bool *ret_colon)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the segment, brightness and color data as set by
segment_display_4x7_set_segments()
.
segment_display_4x7_start_counter
(SegmentDisplay4x7 *segment_display_4x7, int16_t value_from, int16_t value_to, int16_t increment, uint32_t length)¶Parameters: |
|
---|---|
Returns: |
|
Starts a counter with the from value that counts to the to value with the each step incremented by increment. length is the pause between each increment.
Example: If you set from to 0, to to 100, increment to 1 and length to 1000, a counter that goes from 0 to 100 with one second pause between each increment will be started.
Using a negative increment allows to count backwards.
You can stop the counter at every time by calling segment_display_4x7_set_segments()
.
segment_display_4x7_get_counter_value
(SegmentDisplay4x7 *segment_display_4x7, uint16_t *ret_value)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the counter value that is currently shown on the display.
If there is no counter running a 0 will be returned.
segment_display_4x7_get_identity
(SegmentDisplay4x7 *segment_display_4x7, 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: |
|
---|---|
Output Parameters: |
|
Returns: |
|
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.
segment_display_4x7_register_callback
(SegmentDisplay4x7 *segment_display_4x7, int16_t callback_id, void (*function)(void), void *user_data)¶Parameters: |
|
---|
Registers the given function
with the given callback_id
. The
user_data
will be passed as the last parameter to the function
.
The available callback IDs with corresponding function signatures are listed below.
Callbacks can be registered to receive time critical or recurring data from the
device. The registration is done with the segment_display_4x7_register_callback()
function:
void my_callback(int value, void *user_data) { printf("Value: %d\n", value); } segment_display_4x7_register_callback(&segment_display_4x7, SEGMENT_DISPLAY_4X7_CALLBACK_EXAMPLE, (void (*)(void))my_callback, NULL);
The available constants with corresponding function signatures are described below.
Note
Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
SEGMENT_DISPLAY_4X7_CALLBACK_COUNTER_FINISHED
¶void callback(void *user_data)
Callback Parameters: |
|
---|
This callback is triggered when the counter (see segment_display_4x7_start_counter()
) is
finished.
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.
segment_display_4x7_get_api_version
(SegmentDisplay4x7 *segment_display_4x7, uint8_t ret_api_version[3])¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.
segment_display_4x7_get_response_expected
(SegmentDisplay4x7 *segment_display_4x7, uint8_t function_id, bool *ret_response_expected)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
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
segment_display_4x7_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:
segment_display_4x7_set_response_expected
(SegmentDisplay4x7 *segment_display_4x7, uint8_t function_id, bool response_expected)¶Parameters: |
|
---|---|
Returns: |
|
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:
segment_display_4x7_set_response_expected_all
(SegmentDisplay4x7 *segment_display_4x7, bool response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
SEGMENT_DISPLAY_4X7_DEVICE_IDENTIFIER
¶This constant is used to identify a Segment Display 4x7 Bricklet.
The segment_display_4x7_get_identity()
function and the IPCON_CALLBACK_ENUMERATE
callback of the IP Connection have a device_identifier
parameter to specify
the Brick's or Bricklet's type.
SEGMENT_DISPLAY_4X7_DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Segment Display 4x7 Bricklet.