How to Charge a Battery and Switch Power Supply from Adapter to Battery

Recently I've designed a system that use a battery as a backup power.  It can shutdown the power supply by software.  And also automatically switch power supply from adapter to internal battery.

so here is the circuit diagram.

STM32 Multiple USART Driver

Recently, I am developing a small project which utilize many many uart device. The core controller chip is a STM32 Cortex-M3 Chip which has 5 UARTS.  In order to make full use of these UART interface, I just customized a small USART Driver which can make full control of 5 UARTS.

Due to STM32’s restrictions , only UART1 to UART 4 has the ability of DMA Write, so

EDN Design Ideas – Download Them All from 1999 to 2009

Recently, My favourite magazine EDN have changed their website style. But it caused many problem. Now I cannot find new design ideas from the website.  So I just make a google , it tell me that they just hidden the design ideas to magazine issue page. here is the link.

But for your convience, I uploaded all design ideas from Year 1999 to Year 2009, 11 years in all.  You can download them all

[Link]1999-2009.7z

Very First Post of My Very First Blog

Hi, everybody. This is a blog site which mainly focus on the Technical stuff ranges from electronics design example, principle behind a circuit , how to program, and so on.

My Name is Chenxiang Hsu. And I am an electronics designer which work in a small company dealing with hardware design job.  If you wanna to talk with me, just write a email to me