555 based Reset Generator - del50008
You must have read all the circuits and
explanation on the other pages at delabs to
understand this, as i cannot repeat the same thing
as i have done it more than once already.
8051 Single Board Computer - This is just
like the SBC i did decades before using 80C31,
before the Internet.
The circuit is a 555 monostable, The push-switch
is to trigger and generate a reset pulse for uC.
The diode is for OR' ing later. The High will go
thru the diode but the Low of 555 cannot drink any
current as diode blocks.
555 multivibrator like power oscillator
The bottom part of the Circuit is the CD4093
Schmitt nand based flipflop. This is my favorite
because of studying designs in Elektor
What is the Schmitt then ?, It is better to visit
the links below to learn. It can make a sine or
triangle or any shape waveform to square. It can
help square a very messy waveform.
Two nand gates are connected to form a flip-flop
toggle switch. When 555 gives out a pulse, the pulse
is delayed by a R-C which results in a ramp, the
third nand-Schmitt gives out delayed low trigger to
toggle nand-flipflop-switch. The Nand-toggle-switch
is rest at any time with the lower pushbutton. The
fourth nand output gate is not really required. But
the 4093 is quad nand, so unused nand inputs should
not float , pull-up or pull-down. So it has just
been added in circuit so that he can fit some role,
or else he will be bored.
Now you can figure out how such blocks can be used
like Lego blocks
in your own amazing designs
Trigger Voltage in 555
Trigger VoltageThe pulse/level at pin 2 should drop
below 1/3 Vcc before the timer triggers.