

Nand / Nor
i know any gate can convert to NAND or NOR, asked many time why people always use NAND instead of NOR, no one can answer, but i found the answer now. NAND need voltage, NOR need current.
香港搞open source搞唔起的原因
香港永遠唔會出到外國咁成功同大型的open source project, 原因如下: 原因一: 香港無錢 香港人最驚被人話無錢, 但係開源呢單野上正正就係無錢, 可以話係窮到一蚊都無嗰種. 唔信你可以申請下創新科技署同科學園, 你話你搞open source睇下批唔批到條毛俾你. 原因二: 香港人無堅持力同投入度 你可能會反駁香港人都搞好多open source project, 但係得罪講句啲project係停留係小工具嘅層面(我唔係串, 我只係講事實), 係級數同規模上無得同外國比. 至於點解呢世做小工具, 原因不外乎香港人堅持同投入度都極度低下, 無人可以做一單野用十年做單位. 原因三: 香港人好鐘意得個噏字 香港真係太多阿叔, 可以睇 創科阿叔心理分析 原因四: 香港人啲技術低 HK developer = App developer, 個底係打工仔一名, 啲咩科學改變世界唔會關佢地事, 佢地只關心轉工. 原因五: 香港學界無力 香港嘅學界基本上一蚊都揾唔到sponsor, 如果你揾啲教授合作, 佢地唔係自己着數哂就唔會做, 一係就係咁得個吹字. 講技術, 香港學界有幾多料大家都知, 出論文可能得, 但要開發啲實際野唔洗諗. 原因六: 香港無一群有科學使命嘅老細 所有老細為賺錢, 佢地可能都係讀科學出身, 但個底唔係科學人, 可以話一啲科學精神都無. 佢地搞野要三個月後攞出去賣,…
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Heltec Arduino super simple tutorial
Buy from here. Offical website. Steps to make it work in arduino: 3. Burn these examples To try the wifi example 2. Change the wifi ID and password, case sensitive 3. Run it and see the result in serial monitor, set the baudrate to 115200. It grab the html from outside, see the code then…
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Arduino Nano V3.0 + NRF24L01
This little board is nearly the same size as nano but embedded with a NRF24L01, and also very cheap $4 USD. To make it works: The “RF24 > Scanner” will works like below 100% compatible with Arduino nano


Programming Arduino using STK500 ISP
STK500 is better than MKII since it supports high voltage programming, it can reset fuses from any status. Step 1: Install the driver. Must be version from date 7th Oct Plug in the USB, if it detected wrong driver, update it by select specific folder’. Need reboot the computer to take effect. Step 2: connect…
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Programming Arduino using MKII ISP
I got MKII ISP from here. To program Arduino Nano via Microchip studio, nothing special, remember have to select the chip. And Nano D8 pin is B0. Nano bootloader can be found in here.


solder resistors to make oled change from spi to i2c
Arduino To make it work in Arduino, don’t use adafruit SSD1306, you have to use SSH110X library. Run the example, no need to modify anycode.

STM32 + OLED 0.96 4pins I2C, works
This video works https://www.youtube.com/watch?v=Mt6U30Yxrr8&t=311s , sample code is in here.

Arduino Nano IIS + Oled
this youtube works. Oled 0.91 and 0.96 inch both work. Oled can buy in here. The adafruit example is 128×32, need to change to 128×64 for 0.96 inch oled. One thing becareful, 0.96 oled 128×64, the address is still 0x3c, not 0x3d In Arduino IDE, change the address to “3C”, otherwise won’t work

Teaching teenagers to understand logic
Teaching always sharpen my knowledge, fill up all the missing gap of my skill

ATMega 328p use ext 16M oscilator
https://www.ee-diary.com/2021/06/how-to-program-atmega328p-using-atmel.html

Step to run icesugar-nano
Bought from here. user manual: https://github.com/wuxx/icesugar-nano/blob/main/README.mdwin 7 serial driver: https://github.com/wuxx/icesugar-nano/blob/main/doc/usbser.infsource and semantics: https://github.com/wuxx/icesugar-nano Follow https://projectf.io/posts/building-ice40-fpga-toolchain/ . If you got this error: fatal error: ‘ftdi.h’ file not found, then modify config.mk in /Users/peter/workspace/icestorm: Edit /Users/peter/workspace/icestorm/iceprog/Makefile All examples in https://github.com/wuxx/icesugar-nano , just drag the demo program from demo folder or build it…
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ESP32 on arduino, simplest tutorial
Got this board from Taobao. Follow https://randomnerdtutorials.com/installing-the-esp32-board-in-arduino-ide-windows-instructions. schematic:https://pan.baidu.com/s/1sNCK3Z4ZXfziKoF-ZYDMiw Code:pxc4doc:https://pan.baidu.com/s/1SJFlgyIenaM4-TfmT1eLtQ Code:NICE or download here If you failed to run the code for this. Hold “Boot” button while uploading the code If you meet “the port doesn’t exist”, do:

Create a dummy driver for openocd
We are developing our own risc-v so we need to have to ability to modify openocd. Here is the quickest guide for you to start when you type “set $s1=0xaabb”, it will jump to here

Very small STM32 board
Buy from here https://item.taobao.com/item.htm?spm=a1z09.2.0.0.67002e8deFDqTo&id=630403001847&_u=bbuhab0778e , model is STM32F103C8T6

Basic tutorial for blinking led for STM32F411
Tutorial: Create the project Step 1: Open STM32IDE, create the project, choose the right MCU Step 2: Type in project name Step 3: This is project structure Step 4: LED is assign to PC13, set it to GPIO output Then it will generate the setup code Step 5: Blink the led in main, there is…
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PNP create a new list get 403 access denied
Create a new list in SPO via PNPjs will get 403 access denied, run this script to solve it
Load jar and dynamically create object from it
Two maven project, project A load the project B jar, create the object dynamically and invoke the method Project A: Project A: Project B:

SEMU call graph
This graph generated by graphviz, helping students easier understand Professor Jim Huang’s SEMU RISC-V emulator
