Programmable LED dot matrix display system

[cwt]

Thanks p3t3rv! Thanks for your suggestion..
Arigato!!
Thankx Exo...now i know what you mean! :lol:
I apologise for what i did to you..~sorry~

You know why i am not switching to parallel ports?
Because i find it fun to construct in serial communication.
As a student, i hope to learn more.
Another reason is my supervisor ask me to do it in serial communication.
Hope you all dont mind..

 

[cwt]

Hi..now i am at the stage of shifting bits column-by column in the dot matrix array. Now i need a driver to drive those task. Is there any suitable driver to recommend?

I am using a 8x8 dot matrix array.

 

[cwt]

Hi..
I have something to ask about the MAX232 chip.

What is the capacitors used for in the MAX232 chip?

How to select the value of capacitors?

*I am using the MAX232 output to drive some ICs.

 

[Nigel Goodwin]

Hi..
I have something to ask about the MAX232 chip.

What is the capacitors used for in the MAX232 chip?

They are used in charge pump circuits to generate the +10V and -10V supplies.

How to select the value of capacitors?

Use the values off the datasheet, or if you like, look at my RS232 tutorial hardware, where I got the values off the datasheet.

 

[Exo]

why would you need a max232? You only receive from the pc don't you? you dont send anything back...

A simple resistor and diode (to clamp it to 5V) would do...

 

[cwt]

Thx Exo...that sounds interesting. :roll:
However, i already bought the chip and is ready to be implemented..so..i'll stick to MAX232.

 

[Exo]

https://www.qsl.net/yo5ofh/hobby circuits/computer_circuits.htm

This may be of interest to you...

 

[cwt]

Hi out there... :lol:
I have something to ask about my programming stuff. Currently i am using visual basic 6.0 to do my programming.

What i want is like that:

Base on an ASCII character, my program will able to find the pattern that represent the character and display it on the dot matrix array.

How am i going to store all the patterns for each of the ASCII character? :?:
Eg. for the character 'A', the equivalent display pattern is [c1,b7,77,b7,c1].
*Note: all display pattern is in hex.

How am i going to retreive the pattern for each ASCII character? :?:
Eg. for the character 'A', the display pattern [c1,b7,77,b7,c1] will be send out to the dot matrix array.

Thanks!! :wink:

 

[Exo]

Create a 2 dimensional array and load it with your hex values

Dim HexData(X, Y) as integer     'where X is the amount of characters and Y is the number of hex bytes per character

 

[cwt]

Hi...

Is A (a string type) has the same value as A (a hex type)?

Let say A has the character pattern of [c1,b7,77,b7,c1], how am i going to send those patterns out as hex values?

 

[Exo]

A string is an array of bytes wich contains text, it's not meant to hold hex data...

what you need is a 2 dimensional array like this

Dim HexData(20, 5) as integer

this would make space for 20 characters data, 5values per charachter
then you load your data into it

HexData(1, 1) = &HC1
HexData(1, 2) = &HB7
HexData(1, 3) = &H77
and so on

now if you need to send a certain character, let's say character number stored in variable CharToSend you do it like this

for Loop = 1 to 5 do
Output = HexData(CharToSend, Loop)
Next Loop

where Output should be replaced with whatever means of output you are using...

 

[cwt]

Wow~!!! :shock:

If initialise like that, the command will be very very long. Anyway, i get what you mean. I'll try that out.

Thanks~!! :wink:

 

[cwt]

Hi..
Currently i am at the stage of shifting serial bits into parallel bits. I am using an UART PC16550D to do the shifting. I have a few doubts.

Besides taking care of the serial input pin and parallel output pins, what other pins should i included? :?:

Here is a diagram of the chip.

**broken link removed**

Thanks! :lol: