This is the description of the Perl API bindings for the E-Paper 296x128 Bricklet. General information and technical specifications for the E-Paper 296x128 Bricklet are summarized in its hardware description.
An installation guide for the Perl API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Download (example_hello_world.pl)
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 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletEPaper296x128;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your E-Paper 296x128 Bricklet
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $ep = Tinkerforge::BrickletEPaper296x128->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Use black background
$ep->fill_display($ep->COLOR_BLACK);
# Write big white "Hello World" in the middle of the screen
$ep->draw_text(16, 48, $ep->FONT_24X32, $ep->COLOR_WHITE, $ep->ORIENTATION_HORIZONTAL,
"Hello World");
$ep->draw();
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_load_image.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #!/usr/bin/perl
use strict;
use Math::Trig;
use Term::ReadKey;
use GD;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletEPaper296x128;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your E-Paper 296x128 Bricklet
use constant WIDTH => 296;
use constant HEIGHT => 128;
# Convert GD Image to matching color bool array
sub bool_array_from_image
{
my ($image, $cmp_r, $cmp_g, $cmp_b) = @_;
my @pixels = ();
foreach my $row (0..&HEIGHT - 1) {
foreach my $column (0..&WIDTH - 1) {
(my $r, my $g, my $b) = $image->rgb($image->getPixel($column, $row));
$pixels[$row*&WIDTH + $column] = (($r == $cmp_r) && ($g == $cmp_g) && ($b == $cmp_b));
}
}
return @pixels;
}
GD::Image->trueColor(1);
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $epaper = Tinkerforge::BrickletEPaper296x128->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Download example image here:
# https://raw.githubusercontent.com/Tinkerforge/e-paper-296x128-bricklet/master/software/examples/tf_red.png
my $image = newFromPng GD::Image('tf_red.png');
# Get black/white pixels from image and write them to the Bricklet buffer
my @pixels_bw = bool_array_from_image($image, 0xFF, 0xFF, 0xFF);
$epaper->write_black_white(0, 0, &WIDTH-1, &HEIGHT-1, \@pixels_bw);
# Get red pixels from image and write them to the Bricklet buffer
my @pixels_red = bool_array_from_image($image, 0xFF, 0, 0);
$epaper->write_color(0, 0, &WIDTH-1, &HEIGHT-1, \@pixels_red);
# Draw buffered values to the display
$epaper->draw();
print "Press key to exit\n";
ReadMode(0);
$ipcon->disconnect();
|
Generally, every subroutine of the Perl bindings can report an error as
Tinkerforge::Error
object via croak()
. The object has a
get_code()
and a get_message()
subroutine. There are different
error code:
All functions listed below are thread-safe.
BrickletEPaper296x128
->
new
($uid, $ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID $uid
:
$e_paper_296x128 = BrickletEPaper296x128->new("YOUR_DEVICE_UID", $ipcon);
This object can then be used after the IP Connection is connected.
BrickletEPaper296x128
->
draw
()¶Returns: |
|
---|
Draws the current black/white and red or gray buffer to the e-paper display.
The Bricklet does not have any double-buffering. You should not call
this function while writing to the buffer. See get_draw_status()
.
BrickletEPaper296x128
->
get_draw_status
()¶Returns: |
|
---|
Returns one of three draw statuses:
You can write to the buffer (through one of the write or draw functions) when the status is either idle or drawing. You should not write to the buffer while it is being copied to the display. There is no double-buffering.
The following constants are available for this function:
For $draw_status:
BrickletEPaper296x128
->
write_black_white
($x_start, $y_start, $x_end, $y_end, \@pixels)¶Parameters: |
|
---|---|
Returns: |
|
Writes black/white pixels to the specified window into the buffer.
The pixels are written into the window line by line top to bottom and each line is written from left to right.
The value 0 (false) corresponds to a black pixel and the value 1 (true) to a white pixel.
This function writes the pixels into the black/white pixel buffer, to draw the
buffer to the display use draw()
.
Use write_color()
to write red or gray pixels.
BrickletEPaper296x128
->
read_black_white
($x_start, $y_start, $x_end, $y_end)¶Parameters: |
|
---|---|
Returns: |
|
Returns the current content of the black/white pixel buffer for the specified window.
The pixels are read into the window line by line top to bottom and each line is read from left to right.
The current content of the buffer does not have to be the current content of the display. It is possible that the data was not drawn to the display yet and after a restart of the Bricklet the buffer will be reset to black, while the display retains its content.
BrickletEPaper296x128
->
write_color
($x_start, $y_start, $x_end, $y_end, \@pixels)¶Parameters: |
|
---|---|
Returns: |
|
The E-Paper 296x128 Bricklet is available with the colors black/white/red and black/white/gray. Depending on the model this function writes either red or gray pixels to the specified window into the buffer.
The pixels are written into the window line by line top to bottom and each line is written from left to right.
The value 0 (false) means that this pixel does not have color. It will be either black
or white (see write_black_white()
). The value 1 (true) corresponds to a red or gray
pixel, depending on the Bricklet model.
This function writes the pixels into the red or gray pixel buffer, to draw the buffer
to the display use draw()
.
Use write_black_white()
to write black/white pixels.
BrickletEPaper296x128
->
read_color
($x_start, $y_start, $x_end, $y_end)¶Parameters: |
|
---|---|
Returns: |
|
Returns the current content of the red or gray pixel buffer for the specified window.
The pixels are written into the window line by line top to bottom and each line is written from left to right.
The current content of the buffer does not have to be the current content of the display. It is possible that the data was not drawn to the display yet and after a restart of the Bricklet the buffer will be reset to black, while the display retains its content.
BrickletEPaper296x128
->
fill_display
($color)¶Parameters: |
|
---|---|
Returns: |
|
Fills the complete content of the display with the given color.
This function writes the pixels into the black/white/red|gray pixel buffer, to draw the buffer
to the display use draw()
.
The following constants are available for this function:
For $color:
BrickletEPaper296x128
->
draw_text
($position_x, $position_y, $font, $color, $orientation, $text)¶Parameters: |
|
---|---|
Returns: |
|
Draws a text with up to 50 characters at the pixel position (x, y).
You can use one of 9 different font sizes and draw the text in black/white/red|gray. The text can be drawn horizontal or vertical.
This function writes the pixels into the black/white/red|gray pixel buffer, to draw the buffer
to the display use draw()
.
The font conforms to code page 437.
The following constants are available for this function:
For $font:
For $color:
For $orientation:
BrickletEPaper296x128
->
draw_line
($position_x_start, $position_y_start, $position_x_end, $position_y_end, $color)¶Parameters: |
|
---|---|
Returns: |
|
Draws a line from (x, y)-start to (x, y)-end in the given color.
This function writes the pixels into the black/white/red|gray pixel buffer, to draw the buffer
to the display use draw()
.
The following constants are available for this function:
For $color:
BrickletEPaper296x128
->
draw_box
($position_x_start, $position_y_start, $position_x_end, $position_y_end, $fill, $color)¶Parameters: |
|
---|---|
Returns: |
|
Draws a box from (x, y)-start to (x, y)-end in the given color.
If you set fill to true, the box will be filled with the color. Otherwise only the outline will be drawn.
This function writes the pixels into the black/white/red|gray pixel buffer, to draw the buffer
to the display use draw()
.
The following constants are available for this function:
For $color:
BrickletEPaper296x128
->
set_update_mode
($update_mode)¶Parameters: |
|
---|---|
Returns: |
|
Note
The default update mode corresponds to the default e-paper display manufacturer settings. All of the other modes are experimental and will result in increased ghosting and possibly other long-term side effects.
If you want to know more about the inner workings of an e-paper display take a look at this excellent video from Ben Krasnow: https://www.youtube.com/watch?v=MsbiO8EAsGw.
If you are not sure about this option, leave the update mode at default.
Currently there are three update modes available:
With the black/white/red display if you use either the black/white or the delta mode, after a while of going back and forth between black and white the white color will start to appear red-ish or pink-ish.
If you use the aggressive delta mode and rapidly change the content, we recommend that you change back to the default mode every few hours and in the default mode cycle between the three available colors a few times. This will get rid of the ghosting and after that you can go back to the delta mode with flicker-free updates.
The following constants are available for this function:
For $update_mode:
BrickletEPaper296x128
->
get_update_mode
()¶Returns: |
|
---|
Returns the update mode as set by set_update_mode()
.
The following constants are available for this function:
For $update_mode:
BrickletEPaper296x128
->
set_display_type
($display_type)¶Parameters: |
|
---|---|
Returns: |
|
Sets the type of the display. The e-paper display is available in black/white/red and black/white/gray. This will be factory set during the flashing and testing phase. The value is saved in non-volatile memory and will stay after a power cycle.
The following constants are available for this function:
For $display_type:
BrickletEPaper296x128
->
get_display_type
()¶Returns: |
|
---|
Returns the type of the e-paper display. It can either be black/white/red or black/white/gray.
The following constants are available for this function:
For $display_type:
BrickletEPaper296x128
->
set_display_driver
($display_driver)¶Parameters: |
|
---|---|
Returns: |
|
Sets the type of display driver. The Bricklet can currently support SSD1675A and SSD1680. This will be factory set during the flashing and testing phase. The value is saved in non-volatile memory and will stay after a power cycle.
The following constants are available for this function:
For $display_driver:
New in version 2.0.3 (Plugin).
BrickletEPaper296x128
->
get_display_driver
()¶Returns: |
|
---|
Returns the e-paper display driver.
The following constants are available for this function:
For $display_driver:
New in version 2.0.3 (Plugin).
BrickletEPaper296x128
->
get_spitfp_error_count
()¶Return Array: |
|
---|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
BrickletEPaper296x128
->
set_status_led_config
($config)¶Parameters: |
|
---|---|
Returns: |
|
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:
BrickletEPaper296x128
->
get_status_led_config
()¶Returns: |
|
---|
Returns the configuration as set by set_status_led_config()
The following constants are available for this function:
For $config:
BrickletEPaper296x128
->
get_chip_temperature
()¶Returns: |
|
---|
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.
BrickletEPaper296x128
->
reset
()¶Returns: |
|
---|
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!
BrickletEPaper296x128
->
get_identity
()¶Return Array: |
|
---|
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.
Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the register_callback()
function of
the device object. The first parameter is the callback ID and the second
parameter the callback function name:
sub my_callback
{
print "@_[0]";
}
$e_paper_296x128->register_callback(BrickletEPaper296x128->CALLBACK_EXAMPLE, 'my_callback')
The callback function will be called from an internal thread of the
IP Connection. In contrast to many other programming languages, variables are
not automatically shared between threads in Perl. If you want to share a global
variable between a callback function and the rest for your program it has to be
marked as :shared
. See the documentation of the threads::shared Perl module for more details.
The available constants with inherent number and type of parameters 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.
BrickletEPaper296x128
->
CALLBACK_DRAW_STATUS
¶Callback Parameters: |
|
---|
Callback for the current draw status. Will be called every time the
draw status changes (see get_draw_status()
).
The following constants are available for this function:
For $draw_status:
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.
BrickletEPaper296x128
->
get_api_version
()¶Return Array: |
|
---|
Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.
BrickletEPaper296x128
->
get_response_expected
($function_id)¶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
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 $function_id:
BrickletEPaper296x128
->
set_response_expected
($function_id, $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 $function_id:
BrickletEPaper296x128
->
set_response_expected_all
($response_expected)¶Parameters: |
|
---|---|
Returns: |
|
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.
BrickletEPaper296x128
->
set_bootloader_mode
($mode)¶Parameters: |
|
---|---|
Returns: |
|
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 $status:
BrickletEPaper296x128
->
get_bootloader_mode
()¶Returns: |
|
---|
Returns the current bootloader mode, see set_bootloader_mode()
.
The following constants are available for this function:
For $mode:
BrickletEPaper296x128
->
set_write_firmware_pointer
($pointer)¶Parameters: |
|
---|---|
Returns: |
|
Sets the firmware pointer for 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.
BrickletEPaper296x128
->
write_firmware
(\@data)¶Parameters: |
|
---|---|
Returns: |
|
Writes 64 Bytes of firmware at the position as written by
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.
BrickletEPaper296x128
->
write_uid
($uid)¶Parameters: |
|
---|---|
Returns: |
|
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.
BrickletEPaper296x128
->
read_uid
()¶Returns: |
|
---|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.
BrickletEPaper296x128
->
DEVICE_IDENTIFIER
¶This constant is used to identify a E-Paper 296x128 Bricklet.
The get_identity()
function and the
IPConnection->CALLBACK_ENUMERATE
callback of the IP Connection have a device_identifier
parameter to specify
the Brick's or Bricklet's type.
BrickletEPaper296x128
->
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a E-Paper 296x128 Bricklet.