Text Video Display

8BIT · Post by **8BIT** » Tue May 04, 2004 2:07 pm

Hey everyone,

An article about my video display board was published in the May 2004 issue of Nuts & Volts Magazine. Ckeck it out if you have the chance.

Thanks!

Daryl

8BIT · Post by **8BIT** » Tue May 04, 2004 2:08 pm

asm_2750 wrote:

Nice aritcle Daryl.

I guess so...I have not received my issue yet!

Thanks!

Daryl

8BIT · Post by **8BIT** » Sat Aug 21, 2004 4:34 am

I still have PCB's and preprogrammed controllers available for anyone interested in building a composite video text display.

See my web site for details.

Thanks!

Daryl

http://users.softcom.net/darylr/io/vid3.html

sunsea78 · Post by **sunsea78** » Fri Dec 10, 2004 9:09 am

i need atmega8 hex code..
please..

8BIT · Post by **8BIT** » Fri Dec 10, 2004 3:38 pm

sunsea78 wrote:

i need atmega8 hex code..
please..

Hi!

The hex code can be downloaded from the Nuts & Volts web site. Here is the link:

ftp://nutsvolts.com/VideoGen.zip

The zip file has the Intel-hex code and two ExpressPCB.com schematics.

Daryl

8BIT · Post by **8BIT** » Fri Dec 10, 2004 5:14 pm

I've decided to release the source code for the ATMega8. It can be downloaded from my web site under the Downloads section.

http://users.softcom.net/darylr/downloads.html

My thanks to all of you who purchased my display boards. I am now working on an LCD text display based on the same hardware.

Happy Holidays!

Daryl

sunsea78 · Post by **sunsea78** » Wed Dec 15, 2004 11:32 am

thanks 8bit

After establishing the circuit we are planning to send the data needed
with the help of the visual basic program to a parallel port for screening the data on the TV screen. But on TV how we will find out witch character will appear where on TV screen. As an example if I would like to register the 1st line 20th column how I will manage to register it.

Exemple:

USD 1,450,000 1,500,000
EURO 1,800,000 1,880,000

example vbasic or ... code , please..

best regards..

8BIT · Post by **8BIT** » Wed Dec 15, 2004 8:01 pm

To move the cursor, you send 1 byte for row, and another for column.
Rows are set by using $A0-$B8 (160-184 decimal)
Columns are set by using $C0-$E7 (192-231 decimal).

To set Row 0, column 20, send $A0 $D3 followed by your ASCII characters. Note my rows and columns start with zero vs. one.

Does this help?

Daryl

sunsea78 · Post by **sunsea78** » Thu Dec 16, 2004 1:37 pm

First of all thank you very much for all the information. More or less I am trying to understand the info. In the mean time let me inform you that I managed to find the chip atmega8 in Turkey and I bought it. But I did not manage to programme it yet. I have a few questions in my mind to share it with you.

1- The connection of the circuit to the PC do we need an other interface?
2- The connection to the Pc has to be from a parallel port. Can we connect via a serial port?
3- "J1 - 14 pin header (7x2x.01 - 103186-7-ND” how are ewe going to send data from the PC’s parallel Port. what is the pin-out?
4- "http://users.softcom.net/darylr/io/vid3.html” in this web page does the first Picture has a source code? Could you please send met he source code? I will be enlightened better.
5- I will be writing the text sending programme in the visual basic programme. Do you have a source code in hand even a small one will be perfect?

I appreciate your help and all the information.
If you would like to contact with me my msn is: mehmet_yl@hotmail.com
And ICQ:12844814 I will be very pleased to contact you.

My best regards,

8BIT · Post by **8BIT** » Thu Dec 16, 2004 8:47 pm

sunsea78 wrote:

1- The connection of the circuit to the PC do we need an other interface?

I don't thing you will more than the 25 pin connector for the parallel port.
If you set the port to standard parallel port, you should be able to connect the 8 data leads from the 74hc573 directly to the 8 data leads of the parallel port. Connect the parallel port strobe to the strobe input and the busy pin to the busy lead of the printer port. I do not have pinouts of the parallel port but you should be able to find them online. If the strobe input is active low, you'll need an inverter as the 75hc573 requires an active high strobe.

Quote:

2- The connection to the Pc has to be from a parallel port. Can we connect via a serial port?

Yes. You can replace the parallel port with an RS-232. Pins 2&3 of the ATM8 are the rxd and txd pins. You'd need to rewrite the video code to support the RS-232 port. You will also need some sort of level conversion for RS-232 such as a MAX232 or MAX233.

Quote:

3- "J1 - 14 pin header (7x2x.01 - 103186-7-ND” how are ewe going to send data from the PC’s parallel Port. what is the pin-out?

The pinout is on my web site. Look for the parts placement diagram. Just above it are the pin labels.

Quote:

4- "http://users.softcom.net/darylr/io/vid3.html” in this web page does the first Picture has a source code? Could you please send met he source code? I will be enlightened better.

The "splash" screen was generated by storing the entire screen contents in the FLASH and doing a block copy. There is no code that actually builds the screen.

Quote:

5- I will be writing the text sending programme in the visual basic programme. Do you have a source code in hand even a small one will be perfect?

Sorry. I do not have any VB code to show you.

Goodluck with your project.

Daryl

sunsea78 · Post by **sunsea78** » Mon Dec 20, 2004 3:52 pm

1.
I will be writting video 12 hex in atmega8's eprom or flash.
2.
the circuit not connected to the PC can we write the banner on the TV screen

help please.. thank you..

8BIT · Post by **8BIT** » Mon Dec 20, 2004 4:17 pm

sunsea78 wrote:

1.
I will be writting video 12 hex in atmega8's eprom or flash.

Write it to Flash. The eeprom space is not used.
Also, the low fuse byte needs to be changed to enable the external Oscillator.
;* Fuse Settings
;* low byte = 0xE0 (default is E1, E0 enables ext Osc mode)
;* hi byte = 0xD9 (default value)

Quote:

2.
the circuit not connected to the PC can we write the banner on the TV screen

Yes, if you do not connect anything to the inputs, the display should still generate the banner on the video output.

8BIT · Post by **8BIT** » Mon Dec 20, 2004 5:00 pm

I had left out the instructions concerning the fuse byte changes in my original post of the source code. The readme.txt file enclosed in the source code zip file has been updated with fuse byte change.

Thanks!

Daryl

sunsea78 · Post by **sunsea78** » Tue Dec 21, 2004 10:04 pm

board not working...
in turkey make pal system....
capture file http://www.ekolbilisim.com/2.zip

where is the problem board ?

help..
thank you..

8BIT · Post by **8BIT** » Tue Dec 21, 2004 10:45 pm

sunsea78 wrote:

board not working...
in turkey make pal system....
capture file http://www.ekolbilisim.com/2.zip

where is the problem board ?

help..
thank you..

There could be a lot of reasons why its not working. What kind of test equip do you have?

Are you sure the ATM8 is programmed properly and that the fuse bytes are properly set?

Is there a good 16MHz clock going to to the ATM8?

Does the 74HC165 have good shift clock and load signals?

Are the sync pulses leaving the ATM8?

There is a small possibility that the detection line for the PAL mode is not being pulled fast enough. The solution there would be to alter the code to make PAL the default format.

To do that, edit the video.asm file. Comment out the following command:
sbis pinc, ackdpin
by placing a ; in front of it.

Code: Select all

...
...
nop
nop
nop
nop						
;sbis	pinc, ackdpin
rjmp	SETPAL				

SETNTSC:	
...
...

Let me know...

Text Video Display

Re: Saw your Video Display on Nuts & Volts

hi all

Re: hi all

thanks 8bit..

thank you ve help !!!

Re: thank you ve help !!!

Fuse Settings

help please...

Re: help please...