MCS51 interfacing...please

[Atunk]

Hello..
Anybody here being professional with Running text(using dot matrix) with mcs51?
I have some questions here about the schematic diagram
1. How to decide to use (?) KΩ for the resistor connecting to the dot matrix ?
2. Why does all the port for accesing row in dot matrix being connected each other but not for the port for accesing column?
3. What is the transistor connecting to each pin of dot matrix use for ?
4. How to decide crystal to use ?
5. As i know, crystal is use for controlling the frequency.. Right ?


Thanks for all ur support....
Atunk

 

[felixcheng]

1. about 4.7k ... you should check dot matrix spec.