Trying to drive this Video Chip

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retepsnikrep

Senior Member
I'm trying to drive the SV2000 video chip which was mentioned in an earlier thread. I may be misunderstanding the serial comms as I have the chip configured as per diagram 1 TTL.

I'm trying to drive it directly using serout with an 8mhz 18x to provide 9600baud data but I get nothing :(

I've tried inverting both Pic output and Sv2000 input :(
Change calibfreq up and down :(

The chip appears to be working as it has some signal at the output and it's internal watchdog is ticking. The 18X is outputing the data I can see it on the output pin. Do I need any conditioning? or can the Picaxe be connected directly to the input of the Sv2000? It says Max232 ttl compatible.

Any ideas

http://www.speechchips.com/shop/item.aspx?itemid=5

My code is

setfreq 8m
pause 1000
serout 4, N4800, (27,42)

Should display welcome screen

Thanks
 
M

moxhamj

New Member
Hmm. Tie pin 6 to 5V and then it should drive directly from a picaxe. I presume a led/1k resistor on leg 3 of the video chip flashes as the data goes in (and a similar led on leg 5 of the video chip flashes once a second - the "I'm alive" signal").

Digital seems ok. Is the video bit wired up right? Chip zapped?

It looks like a very clever chip. Does it drive a TV or a PC terminal?
 
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retepsnikrep

Senior Member
It's supposed to drive a Monitor, basically anything that can display a 75ohm rca composite video signal if I understand it correctly.

I wanted it to drive one of those in car lcd monitors which have an rca compatible input for cameras etc.
 
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moxhamj

New Member
Can you point us to the relevant bit in the manual? I skimmed through it but I got the impression it was for a TV. There are PAL to VGA converters out there (and NTSC to VGA converters as well) and they cost a bit, which suggests this conversion is not trivial. I'm not an expert on video though - maybe someone can shed some more light on this. If the car LCD monitor has an RCA input (yellow?), it may well be compatible with this chip.
 
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boriz

Senior Member
Should you do this first?
Code: 
PAL/SECAM mode = 27,62 = Set CCIR-based mode (624 lines, 50 fps  Europe)

or

NTSC mode = 27,60 = Set RS170-based mode (524 lines, 60 fps US)
 
R

retepsnikrep

Senior Member
retepsnikrep said:
It's supposed to drive a Monitor, basically anything that can display a 75ohm rca composite video signal if I understand it correctly.

I wanted it to drive one of those in car lcd monitors which have an rca compatible input for cameras etc.
Click to expand...
It's supposed to drive one of those monitors with the yellow sockets 75ohm composite video, cheapo weabcams and a host of other video VCR#s etc have composite video in and out.

I did try setting the Video mode to Pal/SEcam/Ntsc but my monitor can display either anyway, I'll have another go today.

Do we all agree it should take the input direct from the Picaxe? Or is it expecting some horrible -12 to +12v on the Input pin.

I note it can be driven direct from a PC serial port with a few extra connections, I might try that.
 
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moxhamj

New Member
I agree - it can be driven by a picaxe if leg 6 is high. But you can always try reconfiguring it for the +/-12V and drive it from a PC. This could be quite a useful chip and I'm keen to see if you can get it working. Can the picaxe read the serial output from the chip? If you can do that, at least you can prove that parity and baud rates etc are correct.
 
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retepsnikrep

Senior Member
;)

OK got it working now with following code. Looks very neat!

Tested using another monitor, and it was my duff monitor, how annoying is that!!! :rolleyes:

setfreq m8
main:

for b0 =32 to 122
pause 1000
serout 0,T4800,(b0)
next b0

goto main
Click to expand...
Wasted the whole day!!!
 
M

moxhamj

New Member
Nifty. Can you post some pictures and a schematic pls. This could be quite a handy little project - maybe it could go to the "completed projects" section?
 
M

moxhamj

New Member
Sweet. I might get one myself. Need to find a good price on an LCD screen with a yellow RCA input...

Hmm - ebay has little TVs for $20 or so that have RCA inputs.

I see the schematic was drawn at 5:30am. That is keen!
 
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