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Old 2nd Mar 2019, 11:13 pm   #96
1100 man
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Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,278
Default Re: Hedghog standards converter

This is proving to be hard work!! On fitting the FPGA board to the completed hedghog board (minus mod chips & hex switch) I get nothing. Not a sausage

5v & 3.3V rails are there as is the 1.8V from IC7.

The only sign of life is the 4Mhz clock is working. Connecting the freq counter to C38/ C39 shows 4Mhz.

Also the 14Mhz clock on the video decoder chip is working.

Scoping the data lines around IC1 and the D/A output resistors shows nothing happening.

Similarly for the SDA & SCL lines:- nothing.

Analogue video input gets as far as pin 1 of IC1 but that's about it.

I can't measure any shorts on the data lines or anywhere else for that matter. Removing the dev board and powering it separately shows the LED's flashing in sequence so I assume that's working OK.

Not sure where to look now. I might disconnect pin 79 on the dev board which says it inhibits the LED operation. It would be interesting to see if the dev board runs once it's connected to the main PCB or if there is something stopping it.

I'm pretty confident I've not made any silly errors on the PCB:- I examined every component & joints with a lens after each component was soldered in.

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