S
[email protected]
- Jan 1, 1970
- 0
Greetings, I am currently having a problem on getting a shift register
to work. I need to pass serial data out into a serial port with the
input data being parallel hence the 74LS166 is implemented. Having gone
through the datasheets many times and making my circuit is patched
correctly, i am still unable to get any output data. I have used an
oscilloscope to observe any changes in waveform but still nothing. I
have changed the chip 3 times juz to make sure it is not faulty but yet
no output at all. A brief description of the circuit is given below,
- The inputs of the shift registers are connected to pushbuttons.
Schmitt triggers are used as well to prevent any debouncing.
- Clock Inhibit is tied to ground.
- Shift/load pin is connected to a pushbutton as well just for testing
purposes. The logic levels of shift/load have been verified. Shift =
high, load = low
- Clock is set at 40 Hz as i need a relatively fast timing for my
application.
Am i missing something in my circuit patchup? Is the clock too fast for
the data to be shifted out? Is the clock inhibit function necessary? Or
am I missing anything that should be take note of? Please advise. Any
help wld be appreciated. Thanks in advance.
Regards
Lincoln
to work. I need to pass serial data out into a serial port with the
input data being parallel hence the 74LS166 is implemented. Having gone
through the datasheets many times and making my circuit is patched
correctly, i am still unable to get any output data. I have used an
oscilloscope to observe any changes in waveform but still nothing. I
have changed the chip 3 times juz to make sure it is not faulty but yet
no output at all. A brief description of the circuit is given below,
- The inputs of the shift registers are connected to pushbuttons.
Schmitt triggers are used as well to prevent any debouncing.
- Clock Inhibit is tied to ground.
- Shift/load pin is connected to a pushbutton as well just for testing
purposes. The logic levels of shift/load have been verified. Shift =
high, load = low
- Clock is set at 40 Hz as i need a relatively fast timing for my
application.
Am i missing something in my circuit patchup? Is the clock too fast for
the data to be shifted out? Is the clock inhibit function necessary? Or
am I missing anything that should be take note of? Please advise. Any
help wld be appreciated. Thanks in advance.
Regards
Lincoln