This is the description of the Shell API bindings for the IO-4 Bricklet. General information and technical specifications for the IO-4 Bricklet are summarized in its hardware description.
An installation guide for the Shell API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Download (example-interrupt.sh)
1 2 3 4 5 6 7 8 9 10 11 | #!/bin/sh
# connects to localhost:4223 by default, use --host and --port to change it
# change to your UID
uid=XYZ
# enable interrupt on pin 0: (1 << 0) = 1
tinkerforge call io4-bricklet $uid set-interrupt 1
# handle incoming interrupt callbacks
tinkerforge dispatch io4-bricklet $uid interrupt
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1 2 3 4 5 6 7 8 9 10 11 | #!/bin/sh
# connects to localhost:4223 by default, use --host and --port to change it
# change to your UID
uid=XYZ
# set pin 1 to output low: (1 << 1) = 2
tinkerforge call io4-bricklet $uid set-configuration 2 out false
# set pin 2 and 3 to output high: (1 << 2) | (1 << 3) = 12
tinkerforge call io4-bricklet $uid set-configuration 12 out true
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Possible exit codes for all tinkerforge commands are:
The common options of the call and dispatch commands are documented here. The specific command structure is shown below.
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The call command is used to call a function of the IO-4 Bricklet. It can take several options:
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The dispatch command is used to dispatch a callback of the IO-4 Bricklet. It can take several options:
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The <function> to be called can take different options depending of its kind. All functions can take the following options:
Getter functions can take the following options:
Setter functions can take the following options:
The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.
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The <callback> to be dispatched can take several options:
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Output: | no output |
Sets the output value (high or low) with a bitmask (4bit). A 1 in the bitmask means high and a 0 in the bitmask means low.
For example: The value 3 or 0b0011 will turn the pins 0-1 high and the pins 2-3 low.
Note
This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set-configuration.
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Returns a bitmask of the values that are currently measured. This function works if the pin is configured to input as well as if it is configured to output.
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Output: | no output |
Configures the value and direction of the specified pins. Possible directions are 'i' and 'o' for input and output.
If the direction is configured as output, the value is either high or low (set as true or false).
If the direction is configured as input, the value is either pull-up or default (set as true or false).
For example:
The default configuration is input with pull-up.
The following symbols are available for this function:
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Returns a value bitmask and a direction bitmask. A 1 in the direction bitmask means input and a 0 in the bitmask means output.
For example: A return value of (3, 5) or (0b0011, 0b0101) for direction and value means that:
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Returns the current value of the edge counter for the selected pin. You can configure the edges that are counted with set-edge-count-config.
If you set the reset counter to true, the count is set back to 0 directly after it is read.
New in version 2.0.1 (Plugin).
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Output: | no output |
Configures a monoflop of the pins specified by the first parameter as 4 bit long bitmask. The specified pins must be configured for output. Non-output pins will be ignored.
The second parameter is a bitmask with the desired value of the specified output pins. A 1 in the bitmask means high and a 0 in the bitmask means low.
The third parameter indicates the time (in ms) that the pins should hold the value.
If this function is called with the parameters (9, 1, 1500) or (0b1001, 0b0001, 1500): Pin 0 will get high and pin 3 will get low. In 1.5s pin 0 will get low and pin 3 will get high again.
A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and an IO-4 Bricklet connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds and pin 0 set to high. Pin 0 will be high all the time. If now the RS485 connection is lost, then pin 0 will get low in at most two seconds.
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Returns (for the given pin) the current value and the time as set by set-monoflop as well as the remaining time until the value flips.
If the timer is not running currently, the remaining time will be returned as 0.
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Output: | no output |
Sets the output value (high or low) with a bitmask, according to the selection mask. The bitmask is 4 bit long, true refers to high and false refers to low.
For example: The parameters (9, 4) or (0b0110, 0b0100) will turn pin 1 low and pin 2 high, pin 0 and 3 will remain untouched.
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This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set-configuration.
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Output: | no output |
Configures the edge counter for the selected pins.
The edge type parameter configures if rising edges, falling edges or both are counted if the pin is configured for input. Possible edge types are:
The debounce time is given in ms.
Configuring an edge counter resets its value to 0.
If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.
Default values: 0 (edge type) and 100ms (debounce time)
The following symbols are available for this function:
New in version 2.0.1 (Plugin).
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Returns the edge type and debounce time for the selected pin as set by set-edge-count-config.
The following symbols are available for this function:
New in version 2.0.1 (Plugin).
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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' or 'd'.
The device identifier numbers can be found here.
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Output: | no output |
Sets the debounce period of the interrupt callback in ms.
For example: If you set this value to 100, you will get the interrupt maximal every 100ms. This is necessary if something that bounces is connected to the IO-4 Bricklet, such as a button.
The default value is 100.
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Returns the debounce period as set by set-debounce-period.
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Output: | no output |
Sets the pins on which an interrupt is activated with a bitmask. Interrupts are triggered on changes of the voltage level of the pin, i.e. changes from high to low and low to high.
For example: An interrupt bitmask of 10 or 0b1010 will enable the interrupt for pins 1 and 3.
The interrupt is delivered with the callback interrupt.
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Returns the interrupt bitmask as set by set-interrupt.
Callbacks can be used to receive time critical or recurring data from the device:
tinkerforge dispatch io4-bricklet <uid> example
The available callbacks 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.
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This callback is triggered whenever a change of the voltage level is detected on pins where the interrupt was activated with set-interrupt.
The values are a bitmask that specifies which interrupts occurred and the current value bitmask.
For example:
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This callback is triggered whenever a monoflop timer reaches 0. The parameters contain the involved pins and the current value of the pins (the value after the monoflop).