The 74HC595 driver for Digital Outputs is used to set the digital level of a selected channel on an external GPIO extender. The selected channel includes an optional initial value.
The 74HC595 driver for Digital Inputs has five parameters that have to be configured:
This is the data line which transmits the serial data bits from the client to the extender chip. This pin can be connected to any pin on the Builder Base if not already in use
This is the serial clock line which keeps the transmission of the serial data bits in sync. This pin can be connected to any pin on the Builder Base if not already in use
This is the register clock line which shifts the serial data once transmitted into the output registers which eventually sets the pins to the desired output state. This pin can be connected to any pin on the Builder Base if not already in use
More information regarding the functionality of this device can be found in its datasheet
The channel is the port/pin combination on the chip. Just select from the dropdown list what channel your project connects to
This is the initial output mode of the channel
High: The channel has a logic level of 1 at initialization
Low: The channel has a logic level of 0 at initialization
This is the pinout of the 74HC595 where Q is the output with its corresponding letter
The channel QA is connected to the LED directly through a current limiting resistor.
Different versions of this chip tend to use different naming for the pinouts. The Letters can be displayed as numbers for example, the DS (serial data) pin can be called SER or SERIAL DATA, the RSCLK (serial data clock) can be called SRCLK or SH_CP, the RCLK (register clock) can be called ST_CP and the SRCLK (serial clear) can be called MR.
The voltage level for the assembly
The ground potential for the assembly
GP1 (can be any GP pin)
The DS line
GP0 (can be any GP pin)
The RSCLK line
GP2 (can be any GP pin)
The RCLK line
How to write an App
Navigate to the App Builder and create a new application. You can find the “Digital Out” code object under the “Hardware” Tab in the object drop down menu on the left, or you can also use the search bar.
Drag the “Digital Out” Object onto the canvas.
Next, locate the “Button” Object under the Interface tab and drag it onto the canvas.
Finally, connect the “State” port from the Digital Out Object to the “State” port on the Button Object and save your application.
How to create a firmware
Navigate to the Firmware Builder and create a new firmware file.
Click the “+ Add Hardware” button which will open a modal window. Scroll down in the list to find the “Generic” section and select the “Digital Out” hardware option.
Give your device a name, and click “Add Device”
Next, select the “74HC595” driver under the driver dropdown menu.
For this example we select:
Mode: Initially Low
You may now save your firmware file and upload it to one of your clients.