Electronic circuits

Pull-up resistor

Pull-up resistors are used in electronic logic circuits to ensure that inputs to logic systems settle at expected logic levels if external devices are disconnected.

tri-state (vt)

When outputs are tri-stated (in the Hi-Z state) their influence on the rest of the circuit is removed, and the circuit node will be "floating" if no other circuit element determines its state.



PLL (phase-locked loop)

A PLL is a control system that generates a signal that has a fixed relation to the phase of a "reference" signal.

vim 啟用 syntax color (eg. for bash script)

1. 先試式能否在 vim 中動態切換 color:
按:進入command mode 試試
:syntax on
:syntax off

如果沒有顏色，可能副檔名沒有比對成功，手動設定 syntax filetype:

(例如使用 shell script 的 syntax)

:set syn=sh

2. 編輯 /etc/vim/vimrc
把 syntax on 註解打開
或是只想動到個人設定，只在~/.vimrc 加入"syntax on"

LPC bus (Low Pin Count)

What's LPC ? (from LPC bus in Plug-and-Play-HOWTO)

* a type of slow bus, used for slow "legacy" devices such as serial ports, floppy devices, etc.

* replace old ISA bus: LPC needs fewer pins, and uses a faster clock speed

* its bus for data/address and control is only 4 bits wide (so "low pin count")

* all LPC devices are on-board; there are no LPC slots

* a major chip on the LPC bus is the superio chip

Reference:
Linux Plug And Play How-To - 6.10 LPC Bus

LPC Interface Specification at Intel

http://en.wikipedia.org/wiki/Low_Pin_Count