Connect the following pins between your Arduino and the 74HC165 Breakout Board If you're connecting pins like we did above, it should be easy to test if your hardware is working correctly. The values are printed out cleanly on the Serial Terminal. Once the pins are loaded, we make sure the rest of the pins are in the starting state as described by the datasheet and use the Arduino shiftIn function to pull all 8 A-H pin values into a byte called incoming. We do this by pulling the load pin LOW briefly (5 microseconds). In order to read the state of the pins A-H, we need to tell the shift register to capture the state of the pins. We set the clock and shift pin to initial states (HIGH) as described by the datasheet. It first initializes all the pins we connected to outputs with the exception of the pin we receive serial information on.
Here's a brief rundown of what the code does. With everything hooked up, let's take a look at the firmware. The first register in line would still have its serial in pin connected to ground while the last in the chain would have its serial out connected back to the microprocessor instead of another shift register.ĭon't forget to connect power ( 2V-6V) and ground as well. If you were chaining multiple shift registers together, serial in would be attached to the serial out of the last register. Also, connect serial in (SER_IN) to ground.
This pin is where we receive the serial information from the shift register. For the sake of this example, I'll connect one to a button with a pull up resistor and the rest to power or ground.Ĭonnect the serial out (SER_OUT) to pin 11. If you are testing them, it's recommended to just directly tie them to power or ground to make sure everything is working correctly. Pins A-H can be connected to some type of input like buttons, switches, or a digital transistor circuit. A transition to low on the load pin tells the shift register to grab the current state of the 8 input pins(A-H).
The clock sets the frequency that bits are shifted while the clock enable line allows the clock signal to propagate through to the shifting circuitry.Ĭonnect shift/load (SH/ LD) to pin 8. Connect clock (CLK) to pin 12 and clock enable ( CE) to pin 9.
(Default 12-bit) -ěy James E Logan, - VHDL 2008. This code implements a configurable Serial In, - Parallel Out, Shift Register.
0 kommentar(er)
