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uVGA720 core - No demo?

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  • uVGA720 core - No demo?

    My problem is this :

    1. I have built my own base PCB using the 256 colour scheme for uVGA 720

    2. Used BC547 / BC 557 transistors for the DAC section instead of BC847 / 857 due to availability problems.. And the resistors are normal 1/4w type and not the SMT variety. Are these issues ?

    3. When connected to my PC's monitor, I get no Demo message.

    4. The 5.0V dc is at 5.1 V dc;
    Demo pin 12 is pulled down;
    Hsync pin 9 reads 35.1 kHz;
    Vsync pin 10 reads 32 - 49 Hz - not sure though.

    5. Doubly cross checked the PCB. It is exactly as per your scheme.

    So what can be wrong ? Do I need to set anything on the monitor to make it
    VGA compatible ? I don't suppose so...

    Thanks for any help.