LEAP#394 Arduino 8051 Programmer
I’ve been meaning to dive a bit deeper into Intel MCS-51/8051 devices and programming ever since I built a Electronic Clock Kit powered by an AT89C2051.
Reading the AT89C2051 datasheet, its seems programming is actually a quite straight-forward process - the only complication being the need for a 12V programming voltage in addition to standard logic high of ~5V.
So while I could go out and buy a programmer, I found the idea of building my own is very attractive for two reasons:
- it is a bit of a short cut to building familiarity with the chip and datasheet
- I can make sure it supports my host platform of choice - MacOSX
I borrowed some ides from similar projects, the result being a programmer on an Arduino Uno shield, with discrete charge pump for the 0V-5V-12V required for the various programming modes, and compatible with the Python-based, open source at89overlord programming software written by piotrb5e3.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#393 Dickson Charge Pump
The Dickson Charge Pump is a neat trick for multiplying an input voltage. It is basically a capacitor bucket-brigade, with diodes for flow control, and a switching signal to make it go. It is not the most efficient voltage booster, and cannot drive very high currents, but may be a convenient solution depending on the application.
The version I’ve implemented here runs on an Arduino with a 62kHz PWM signal and generates a zener-regulated 12V output from the 5V supply on the Arduino.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#392 BoldportClub Whiteboard
The BoldportClub project #22 whiteboard is a neat little “breadboard enhancer”, featuring variable and coin-cell power supplies and prototyping areas. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
Here’s a simple demonstration using the 4 LEDs on the shroud as outputs for a 4-stage CD4060 ripple counter:
Also included is a sheet of StickerCAD icons. I used them on my laptop case - including a rebus if you look carefully;-)
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LEAP#391 Packaging the mV Meter
A while back I breadboarded an ATmega328-based millivolt meter based on a design by Scullcom Hobby Electronics. It uses an LTC2400 ADC and LT1019 voltage reference, and has some nice display modes on a 16x2 LCD.
It’s a nice design so I decided to go the whole hog and fab a PCB at OSHpark, but this time using EasyEDA for the schematic capture and board design. Althoughit’s PCB design tools are relatively primative, it turned out just fine!
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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