Category Archives: MCU

8-bit font tool: editor, rotator, mirror

This is small tool writtent in Visual Studio Express VB. Main purpose of this tool is to find 8 bit wide fonts and graphics in various ROM, firmware files and export to binary or C source file. Tool can edit … Continue reading

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PS2 keyboard for ZX Spectrum (or clone)

ZX Spectrum and other computers of that period use proprietary keyboards with direct connection to some specific chip or connected directly to computer bus. Old keyboards are damaged from elementals or time, and sometimes are not very user friendly compared … Continue reading

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Printer from calculator, part 2

Continued from part 1. The printer from the calculator is a neat toy, but we want a real USB printer. So, using my new STM32F103 CubeMX USB printer class for communication with the host computer and some tricky INT based … Continue reading

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Printer from calculator, part 1

In a pile of e-waste I found a printing calculator, Citizen CX-123II. It is a regular calculator (with some wicky calculations), but with a printer- all output from the screen are hard-copied to paper roll. It can print only numbers … Continue reading

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ARM:0018 STM32CubeMX hack – printer class device

This article is about printer class device for STM32F103 and STM32CubeMX. Somehow there is NO printer device class example in whole internet. There ar CDC or HID examples copied from same STM32CubeMX example with minimal explanation, few of mass storage … Continue reading

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ARM:0017 – go to sleep clock

This is a “gamers” clock. It sits near the monitor and shows the real time and time computer is on. This is achieved using USB as power supply. Also, the same USB port is used to set the clock. Battery … Continue reading

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ARM:0016 STM32CubeMX – problems with RTC

This is a very short message about proper initialization of RTC (real time clock). There is one trick designed in HAL and in several internet resources it is wrongly described. Proper RTC init: Find “MX_RTC_Init(void)“, scroll to “USER CODE BEGIN … Continue reading

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ARM:0015 STM32CubeMX screen libraries, part 2

Continued from Part 1. There are lots of different LCD or OLED screens in the market. Typically, it is possible to define 3 types of screens according to interface type: I2C, SPI and parallel data bus. There are also analog … Continue reading

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ARM:0014 STM32CubeMX libraries for sensors and screens

In fact, any new program written for MCU is only copy-paste from older projects. Not real copy paste, but using the same libraries and subroutines. For some upcoming bigger project, I decided to use STM32 microcontroller, this means, I need … Continue reading

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ARM:0013 STM32CubeMX – USB HID keyboard

Now we will build a USB keyboard. This project is based on STM32CubeMX canned example, HID mouse (see previous article). But we will change mouse to keyboard. Both devices are from the same HID class. First we need to change … Continue reading

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