https://captdam.com/English List - Captdam's BlogCopyright Captdam | CC BY-SABearwebhttps://captdam.com/https://captdam.com/favicon.icoSat, 14 Mar 2026 08:12:43 +0000admin@beardle.comhttps://captdam.com/pico-execmem/enhttps://captdam.com/pico-execmem/enCaptdamEmbedded-enCompare RP2040 executable memory regions (flash XIP space, striped SRAM and banked SRAM). Discuss memory strategies, data hazard and structural hazard. Load program from flash into SRAM then execute from SRAM.Thu, 12 Mar 2026 08:18:38 +0000https://captdam.com/pico-clk/enhttps://captdam.com/pico-clk/enCaptdamEmbedded-enCompare the RP2040 clock sources, switch the clock source in bare metal.Sun, 08 Mar 2026 00:36:27 +0000https://captdam.com/pico-multicore/enhttps://captdam.com/pico-multicore/enCaptdamEmbedded-enAnalysis the RP2040 Core 1 launch protocol. Launch core 1 in bare metal multi-processor application with minimum code.Sat, 07 Mar 2026 21:39:05 +0000https://captdam.com/pico-bootloader/enhttps://captdam.com/pico-bootloader/enCaptdamEmbedded-enAnalysis the W25Q flash memory communication and the RP2040 SDK 2nd stage bootloader in disassembled code from the perspective of an 8-bit MCU developer's view.Sat, 07 Mar 2026 21:10:09 +0000https://captdam.com/pico-program-storage/enhttps://captdam.com/pico-program-storage/enCaptdamEmbedded-enProgram the Pico (RP2040) from the perspective of an 8-bit MCU developer’s view, focus on details in SRAM and flash memory programming.Mon, 02 Mar 2026 14:59:28 +0000https://captdam.com/bearweb-resource-optimization/enhttps://captdam.com/bearweb-resource-optimization/enCaptdamComputer-enPHP optimization on the Bearweb CMS to reduce memory usage and chance of OOM.Mon, 02 Feb 2026 05:26:18 +0000https://captdam.com/multilingual-webpage/enhttps://captdam.com/multilingual-webpage/enCaptdamComputer-enIn this article, I will discuss a few ways I used to create multilingual webpages. I will also include my thoughts about the advantages and disadvantages of these ways.Mon, 02 Feb 2026 01:36:58 +0000https://captdam.com/avrld/enhttps://captdam.com/avrld/enCaptdamEmbedded-enThis article discusses how to write assembly code using the GNU avr-as assembler for AVR microprocessor and how to link the object files into AVR executables. Furthermore, it shows how to write a bare metal C program with manual link, and how to write a program with mixed C and assembly code for AVR.Sun, 09 Nov 2025 09:29:56 +0000https://captdam.com/avrgcc/enhttps://captdam.com/avrgcc/enCaptdamEmbedded-enIn this article, a number of experiments are used to examine the output machine code generated by AVR-GCC. Description is given for possible reasons AVR-GCC generates machine code in this way.Sun, 09 Nov 2025 06:41:17 +0000https://captdam.com/tilingpdf/enhttps://captdam.com/tilingpdf/enCaptdamComputer-enDivide large PDF into tiles on multiple page to allow print on small-size paper, suit for map and civil drawingThu, 16 Oct 2025 07:17:24 +0000https://captdam.com/attiny-ws2812/enhttps://captdam.com/attiny-ws2812/enCaptdamEmbedded-enThis article shows how to use AVR MCU (ATtiny) to efficiently drive WS2812 LEDs, that is, using parallel signals to drive segmented LED stripe.Mon, 18 Aug 2025 09:36:08 +0000https://captdam.com/ch340/enhttps://captdam.com/ch340/enCaptdamEmbedded-enI made a very tiny CH340E based USB-UART interface board.Mon, 18 Aug 2025 01:50:08 +0000https://captdam.com/my-attiny/enhttps://captdam.com/my-attiny/enCaptdamEmbedded-enThis blog will introduce ATtiny chips in DIP / SOIC packages and with SPI-based ICSP interface that I have been used in my projects.Tue, 05 Aug 2025 05:36:54 +0000https://captdam.com/avr-call-stack/enhttps://captdam.com/avr-call-stack/enCaptdamEmbedded-enThis article will discuss demonstrate the stack operation of AVR-GCC when calling a function from the hardware's perspective of view.Mon, 03 Mar 2025 05:03:17 +0000https://captdam.com/pdf-titleblock-gen/enhttps://captdam.com/pdf-titleblock-gen/enCaptdamComputer-enMerge, add text, pictures and custom titleblock to PDF engineering drawing, and generate index.Fri, 20 Sep 2024 04:37:29 +0000https://captdam.com/68hc11stringprint/enhttps://captdam.com/68hc11stringprint/enCaptdamEmbedded-enThis article illustrates string structure in memory and how to print string on PC using C and on microprocessor using assembly. Assembly language of 68HC11 is used as example.Mon, 02 Sep 2024 22:55:57 +0000https://captdam.com/avr-naked-isr/enhttps://captdam.com/avr-naked-isr/enCaptdamEmbedded-enUsing naked interrupt service routine (ISR) in AVR developmentSun, 01 Sep 2024 02:23:20 +0000https://captdam.com/cncfabpcb/enhttps://captdam.com/cncfabpcb/enCaptdamEmbedded-enThis blog shows how I use KiCad to design a PCB, then use FlatCAM to generate the G-code for a CNC to engrave on copper plated board. This blog also discusses the challenges I encountered and my solutions.Sat, 31 Aug 2024 05:01:48 +0000https://captdam.com/level-shifter/enhttps://captdam.com/level-shifter/enCaptdamEmbedded-enIntroduce two different level shifter for logic circuit design: the NMOS-based design and the diode-based design. This blog will introduce the working principle of both design, provide PCB layout for both of them using SMD, provide timing diagrams using scope for both implementation, and compare the pros and cons of them.Sat, 23 Dec 2023 21:05:58 +0000https://captdam.com/modbus/enhttps://captdam.com/modbus/enCaptdamEmbedded-enIntroduction to MODBUS and MODBUS RTU protocol. This blog presents the format of MODBUS RTU packet, including the request from master to slave and the response form slave to master. This blog also shows how to ccompute the CRC-16 value for MODBUS packet in AVR assembly language.Sun, 20 Aug 2023 23:00:17 +0000https://captdam.com/nixieclock51/enhttps://captdam.com/nixieclock51/enCaptdamEmbedded-enYou can’t say no to nixie tubes if you are an electrical geek or you are a fan of Steins Gate, and you will want to build a clock using nixie tubes.Wed, 14 Feb 2018 06:11:30 +0000