Programmable LED dot matrix display system

C

cwt

New Member

• May 27, 2004

• #21

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..

 

C

cwt

New Member

• May 28, 2004

• #22

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.

 

C

cwt

New Member

• Jun 3, 2004

• #23

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

Super Moderator

Most Helpful Member

• Jun 3, 2004

• #24

cwt said:

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

What is the capacitors used for in the MAX232 chip?

Click to expand...

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

How to select the value of capacitors?

Click to expand...

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

Active Member

• Jun 4, 2004

• #25

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...

 

C

cwt

New Member

• Jun 5, 2004

• #26

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

Active Member

• Jun 6, 2004

• #27

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

This may be of interest to you...

 

C

cwt

New Member

• Jun 13, 2004

• #28

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

Active Member

• Jun 13, 2004

• #29

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

Code:

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

 

C

cwt

New Member

• Jun 14, 2004

• #30

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

Active Member

• Jun 15, 2004

• #31

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...

 

C

cwt

New Member

• Jun 16, 2004

• #32

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:

 

C

cwt

New Member

• Jun 22, 2004

• #33

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: