8 bit computer, ALU complete
Everything is connected now on the ALU board.
the bus has been connected (blue wires)
the A register is connected to the ALU chips (purple wires)
the B register is connected to the ALU chips (green wires)
the ALU output is connected to the connector… Read the rest
8 bit computer, building up the ALU
The ALU
Building up the heart of the computer, the two big chips are 74LS181’s (4 bit ALU’s, hence there’s two of them). The two little chips below them are the 74LS245 tri-state buffer, that connects it to the bus in a controlled… Read the rest
8 bit computer, building the ALU
I’m in the process of building the Arithmetic and Logic Unit (ALU) for my 8 bit computer. So far, as you can see, the complete B register and half of the A register are built. In the open space in the middle the ALU… Read the rest
Replacement soldering station
My old faithful soldering iron died… It served me well during numerous years, but finally it gave up.
It just does not produce heat anymore.
Soldering station
So, time to select a new one. I decided to go for a temperature controlled one this time and… Read the rest
8 bit computer, program counter and reset
I’m busy transitioning my 8 bit computer from the breadboards I built it on to experimental PCB’s. They will be on a bus print. Here’s the first video:
… Read the rest
Debounce made visible
The problem
When using mechanical switches in electronic circuits we encounter the difficulty of what is called “bouncing”. A switch often contains a spring-like contact that, when pushed, bounces up and down sometimes and in doing so, creates multiple pulses. We only intend to give ONE pulse.… Read the rest
New multimeter, RIGOL DM3058E
In this post, I introduce my new digital bench multimeter, the RIGOL DM3058E. It’s an entry level laboratory precision instrument that will be a good addition to my workbench.
I will present it in the form of an “unboxing”.
Missing was the CD that… Read the rest
Calibration, calibration…
To make sure an instrument measures as precise as it can, it has to be calibrated. My new RIGOL DS1052E has a Utility function called Self-Cal, where it, you guessed it, calibrates itself. I performed this function once when the scope was just on my bench.
I have… Read the rest
Old PSU, further measurements
Today I did some more measurements on the old PSU, see results below.
At 16 Volts, without any load attached, this is what it produces (AC coupled). We see an ugly saw-tooth like voltage of about 80mV and a period of about 350uS.
At 16… Read the rest
Old power supply
The story
This PSU was build by my father back in the 80’s. It has served him well and after he was promoted to glory in 1998 I have used it on my workbench. Today I opened up this old power supply. See photos below:
… Read the rest
Lissajous curves
As you can see, I started with a nice Lissajous curve. This can be accomplished by putting a sine wave on both channels of the oscilloscope and making sure that the frequency on one channel has a specific ratio to the frequency of the other channel.
On the… Read the rest
New oscilloscope on the bench
Positioned on top
Today I did my first experiments and measurements with the new oscilloscope. But first I had to find a logical spot for it. I had planned to put it on my desk, next to my function generator (see this post).
For now,… Read the rest
Oscilloscope arrived!
My new RIGOL DS1052E oscilloscope arrived. I’m one happy nerd now…
Here it is, booting up:
Of course it had to be tested. There’s a calibration signal, generated in the scope itself, especially for the purpose of calibration. So I hooked one of up the probes to… Read the rest