Sunday, January 19, 2014

Oscillator Controller for 8bit PIC Microcontrollers

This is oscillator controller for 8bit PIC microcontrollers which is specifically design to debug MCUs and related circuits by without using ICD unit.

This unit consists with low speed oscillator and cycle counter with automatic hold. In current version, oscillator is capable to run in 2 frequency modes and it can count up to 4096 cycles in each run. The number of frequency modes can be extend by adding more capacitors and the upper limit of cycle counter can be increase by adding more 12bit counters (and related circuitries) to the system.

Oscillator waveform in low frequency mode

In current version oscillator can be run in either 66 Hz ~ 70 Hz or 666 Hz ~ 670 Hz (aprox.). This frequency can be adjusted by changing the value of C1 or C2 capacitors (e.g: 0.1MFD can generate 6.39 kHz output signal) OR by replacing R1 with some suitable variable resistor.

In project package we include sample PIC16F84A based project to test with this system. The recommended test attachment is illustrated in below:

Recommended test attachment for PIC16F84A test code

This is open source hardware project and it is licensed under Creative Commons Attribution 4.0 International License. The complete project package is available to download at

Tuesday, January 14, 2014

3.3V Power Supply Unit

Now a days 3.3V PSU is essential for microcontroller, programmable logic devices and for some analog components also (especially with some new ADCs). This is ultra-simple 3.3V power supply unit, which is suitable for above mentioned experiments. This power supply is based on, ON semiconductor’s MC33269T-3.3 LDO regulator and it is capable to deliver 3.3V output with maximum of 800mA current.

External view of 3.3V Power Supply

The PCB design supplied with this article is also compatible with LD1117V33 (also known as LD33V) LDO regulator and it can use with this PCB without any changes. Dimension of the given PCB is 70mm × 35mm and it is design with all through-hole components. Our PCB design for this PSU is available to download at

Maximum input voltage for this module is 20V (DC) for MC33269T-3.3 and 15V (DC) for LD1117V33 (or LD33V). In our unit we use 230V – 9V (1A) step down transformer as AC input for this unit.

Friday, January 10, 2014

Extended Run dialog box for Windows

When it comes to Windows operating systems I highly addicted to the "Run" dialog box. Technically, to me it functions like a single-line command line interface. From Windows 95 to Windows 8.1, layout and the functionalists of "Run" dialog box is quiet identical.

To extend the functionalists of "Run" dialog box we did some project call "QRun". The main purpose of QRun is to provide more convenient user-interface to existing Windows "Run" dialog box.

QRun window with Action menu entries
The key feature of QRun is its menu driven command and resource selector. This menu driven interface help end user to perform actions by without memorizing commands and/or parameters. Another feature of QRun is its macro commands. Using this feature end user can create custom actions for run dialog box.

Other than above features QRun also had inbuilt support for win-bash. Because of this feature end user may be able to run GNU bash related commands directly from the run dialog box. 

Once installed in a system, user can open QRun by navigating over start menu/screen OR by pressing Shift + WinKey + R key combinations.

QRun is an open source free software project and it is distributed under the terms of MIT license. Latest version of QRun is available to download at Details about manual installations, compiling and configuring of QRun are available at