Keyboard Scanning Using 8255

Hi all I have interfaced 64K SRAM and 8255 PPI to 8051RD2 for scanning Matrix keyboard. On resetting the system all port pins of 8255 go to high impedence state. i am using Memory map technique to...
Keyboard Scanning Using 8255

Hi all I have interfaced 64K SRAM and 8255 PPI to 8051RD2 for scanning Matrix keyboard. On resetting the system all port pins of 8255 go to high impedence state. i am using Memory map technique to...
How to scan strings from keyboard much clever?

I want to scan string from keyboard and display on LCd ,but when scanning the next string ,the buffer for saving pre_string will be changed to the value in scanning buffer,and the display also will be...
How to scan strings from keyboard much clever?

I want to scan string from keyboard and display on LCd ,but when scanning the next string ,the buffer for saving pre_string will be changed to the value in scanning buffer,and the display also will be...
Boundary Scan

Hi can anyone please explain me what's boundary scan in JTAG is?? and how it can be used to check the interconnect in PCB or inside an IC without connecting actual pin??