Electronics – Page 4 – Geronimo/370

8 bit computer, output module, problem solved

Posted on2017-09-24

8 bit computer, output module, problem solved Remember that annoying problem I spoke of? I solved it! It appears I had soldered two connections together by accident. Almost invisible, but still two outputs were connected, resulting in double displays on the two leftmost 7-segment displays. Fortunately I was able to… Read the rest

8 bit computer, instructions and microcode

Posted on2017-09-232019-05-12

When designing and building your own computer, you have to design and build your own instruction set as well. So that’s one of the things I’m doing right now. One of the functions of the Control Unit in the computer is to decode the instructions and have all the chips… Read the rest

8 bit computer, buildup status

Posted on2017-09-21

8 bit computer, buildup status The status so far in pictures: … Read the rest

8 bit computer, output module, annoying problem

Posted on2017-09-17

8 bit computer, output module, annoying problem As you can see in the picture on the right, the output displays two little ‘-‘ signs – and sometimes even more segments – in a dim, lightly flickering way, to the left of the actual output digits. Funny thing is this seems… Read the rest

16 position rotary switch for hex input

Posted on2017-08-27

16 position rotary switch for hex input Found this post for a better input possibility: … Read the rest

8 bit computer, ALU complete

Posted on2017-08-27

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

Posted on2017-08-20

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

Replacement soldering station

Posted on2017-08-18

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, clock circuit

Posted on2017-08-13

8 bit computer, clock circuit The second print I made is the computer clock: … Read the rest

8 bit computer, program counter and reset

Posted on2017-08-12

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

Posted on2017-08-01

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

Posted on2017-07-29

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…

Posted on2017-07-27

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

Posted on2017-07-26

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

Posted on2017-07-25

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